ci: run various combinations to test the build, append a note in the readme

Hm, so far, I was not able to find a way to avoid building the below ifdef place only when Xcode 12 x macOS 11.3-macOS 12 combinations. Xcode 12 x macOS 10 had no issue, I haven't tried as no environment, but maybe macOS 11.0-.2 x Xcode 12 also had no issues.
-fmodules-cache-path\=/Users/runner/Library/Developer/Xcode/DerivedData/ModuleCache.noindex -fmodules-prune-interval\=86400 -fmodules-prune-after\=345600 -fbuild-session-file\=/Users/runner/Library/Developer/Xcode/DerivedData/ModuleCache.noindex/Session.modulevalidation -fmodules-validate-once-per-build-session -Wnon-modular-include-in-framework-module -Werror\=non-modular-include-in-framework-module -Wno-trigraphs -fpascal-strings -O0 -fno-common -Wno-missing-field-initializers -Wno-missing-prototypes -Werror\=return-type -Wdocumentation -Wunreachable-code -Wquoted-include-in-framework-header -Wno-implicit-atomic-properties -Werror\=deprecated-objc-isa-usage -Wno-objc-interface-ivars -Werror\=objc-root-class -Wno-arc-repeated-use-of-weak -Wimplicit-retain-self -Wduplicate-method-match -Wno-missing-braces -Wparentheses -Wswitch -Wunused-function -Wno-unused-label -Wno-unused-parameter -Wunused-variable -Wunused-value -Wempty-body -Wuninitialized -Wconditional-uninitialized -Wno-unknown-pragmas -Wno-shadow -Wno-four-char-constants -Wno-conversion -Wconstant-conversion -Wint-conversion -Wbool-conversion -Wenum-conversion -Wno-float-conversion -Wnon-literal-null-conversion -Wobjc-literal-conversion -Wshorten-64-to-32 -Wpointer-sign -Wno-newline-eof -Wno-selector -Wno-strict-selector-match -Wundeclared-selector -Wdeprecated-implementations -DDEBUG\=1 -DOBJC_OLD_DISPATCH_PROTOTYPES\=0 -isysroot /Applications/Xcode_12.5.1.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.3.sdk -fasm-blocks -fstrict-aliasing -Wprotocol -Wdeprecated-declarations -g -Wno-sign-conversion -Winfinite-recursion -Wcomma -Wblock-capture-autoreleasing -Wstrict-prototypes -Wno-semicolon-before-method-body -Wunguarded-availability -index-store-path /Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Index/DataStore -iquote /Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Build/Intermediates.noindex/WebDriverAgentMac.build/Debug/WebDriverAgentRunner.build/WebDriverAgentRunner-generated-files.hmap -I/Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Build/Intermediates.noindex/WebDriverAgentMac.build/Debug/WebDriverAgentRunner.build/WebDriverAgentRunner-own-target-headers.hmap -I/Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Build/Intermediates.noindex/WebDriverAgentMac.build/Debug/WebDriverAgentRunner.build/WebDriverAgentRunner-all-non-framework-target-headers.hmap -ivfsoverlay /Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Build/Intermediates.noindex/WebDriverAgentMac.build/Debug/WebDriverAgentRunner.build/all-product-headers.yaml -iquote /Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Build/Intermediates.noindex/WebDriverAgentMac.build/Debug/WebDriverAgentRunner.build/WebDriverAgentRunner-project-headers.hmap -I/Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Build/Products/Debug/include -I/Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Build/Intermediates.noindex/WebDriverAgentMac.build/Debug/WebDriverAgentRunner.build/DerivedSources-normal/x86_64 -I/Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Build/Intermediates.noindex/WebDriverAgentMac.build/Debug/WebDriverAgentRunner.build/DerivedSources/x86_64 -I/Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Build/Intermediates.noindex/WebDriverAgentMac.build/Debug/WebDriverAgentRunner.build/DerivedSources -F/Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Build/Products/Debug -iframework /Applications/Xcode_12.5.1.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/Frameworks -MMD -MT dependencies -MF /Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Build/Intermediates.noindex/WebDriverAgentMac.build/Debug/WebDriverAgentRunner.build/Objects-normal/x86_64/WebDriverAgentRunner.d --serialize-diagnostics /Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Build/Intermediates.noindex/WebDriverAgentMac.build/Debug/WebDriverAgentRunner.build/Objects-normal/x86_64/WebDriverAgentRunner.dia -c /Users/runner/work/appium-mac2-driver/appium-mac2-driver/WebDriverAgentMac/WebDriverAgentRunner/WebDriverAgentRunner.m -o /Users/runner/Library/Developer/Xcode/DerivedData/WebDriverAgentMac-bucmjpiialdbpndjdovhzxqnjbmm/Build/Intermediates.noindex/WebDriverAgentMac.build/Debug/WebDriverAgentRunner.build/Objects-normal/x86_64/WebDriverAgentRunner.o
/Users/runner/work/appium-mac2-driver/appium-mac2-driver/WebDriverAgentMac/WebDriverAgentRunner/WebDriverAgentRunner.m:50:81: error: property 'nonStrictOptions' not found on object of type 'XCTExpectedFailureOptions'
  XCTExpectFailureWithOptions(@"Ignore all failures", XCTExpectedFailureOptions.nonStrictOptions);
                                                                                ^

** ANALYZE FAILED **

The following build commands failed:
    Analyze /Users/runner/work/appium-mac2-driver/appium-mac2-driver/WebDriverAgentMac/WebDriverAgentRunner/WebDriverAgentRunner.m normal x86_64
(1 failure)
Error: Process completed with exit code 65.
So... our best possible way is to address the combination does not work in the README..
appium / appium-mac2-driver

ci: run various combinations to test the build, append a note in the readme #173
