Gradle build improvements

[tpreviero]

This PR provide little improvements to the Gradle build.

Description

Here's a brief list of what changed:

• Add com.google.protobuf:protoc dependency for configurations
• Upgrade version of Gradle Enterprise plugin to version 3.12.4
• Upgrade version of com.gorylenko.gradle-git-properties to version 2.4.1
• Use mavenCentral instead of jcenter as repository
• Use archiveFileName instead of deprecated archiveName property
• Extract swagger download from copySwagger task Explicitly define inputs and outputs for copyGWActions task

Related issue and scope

• [ ] I opened an issue to propose and discuss this change (#????)

My changes affect the following components

• [ ] API
• [ ] Controller
• [ ] Message Bus (e.g., Kafka)
• [ ] Loadbalancer
• [ ] Scheduler
• [ ] Invoker
• [ ] Intrinsic actions (e.g., sequences, conductors)
• [ ] Data stores (e.g., CouchDB)
• [ ] Tests
• [ ] Deployment
• [ ] CLI
• [x] General tooling
• [ ] Documentation

Types of changes

• [ ] Bug fix (generally a non-breaking change which closes an issue).
• [ ] Enhancement or new feature (adds new functionality).
• [ ] Breaking change (a bug fix or enhancement which changes existing behavior).

Checklist:

• [x] I signed an Apache CLA.
• [x] I reviewed the style guides and followed the recommendations (Travis CI will check :).
• [ ] I added tests to cover my changes.
• [ ] My changes require further changes to the documentation.
• [ ] I updated the documentation where necessary.

[codecov-commenter]

Codecov Report

Merging #5387 (770fc71) into master (60ca660) will decrease coverage by 0.63%. The diff coverage is n/a.

:exclamation: Current head 770fc71 differs from pull request most recent head 67447e9. Consider uploading reports for the commit 67447e9 to get more accurate results

@@            Coverage Diff             @@
##           master    #5387      +/-   ##
==========================================
- Coverage   76.91%   76.29%   -0.63%     
==========================================
  Files         240      233       -7     
  Lines       14588    14324     -264     
  Branches      629      625       -4     
==========================================
- Hits        11221    10928     -293     
- Misses       3367     3396      +29     

see 24 files with indirect coverage changes

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[style95]

It seems this error is happening.

org.apache.openwhisk.standalone.StandaloneApiGwTests > classMethod FAILED
    java.lang.IllegalArgumentException: requirement failed
        at scala.Predef$.require(Predef.scala:268)
        at org.apache.openwhisk.standalone.StandaloneApiGwTests.$anonfun$waitForOtherThings$1(StandaloneApiGwTests.scala:39)