feat: add Invocable scripts API

[bednar]

Proposed Changes

1. Added API for InvocableScripts.
2. Changed supported InfluxDB version from InfluxDB 2.0 to InfluxDB 2.x

Checklist

• [x] CHANGELOG.md updated
• [x] Rebased/mergeable
• [x] A test has been added if appropriate
• [x] make test completes successfully
• [x] Commit messages are in semantic format
• [x] Sign CLA (if not already signed)

[codecov-commenter]

Codecov Report

Merging #119 (48294b0) into master (d5abfd8) will decrease coverage by 0.60%. The diff coverage is 60.00%.

:exclamation: Current head 48294b0 differs from pull request most recent head 0ca2694. Consider uploading reports for the commit 0ca2694 to get more accurate results

@@             Coverage Diff              @@
##             master     #119      +/-   ##
============================================
- Coverage     81.83%   81.22%   -0.61%     
- Complexity      384      394      +10     
============================================
  Files            23       24       +1     
  Lines           903      911       +8     
============================================
+ Hits            739      740       +1     
- Misses          164      171       +7     

Impacted Files	Coverage Δ
src/InfluxDB2/QueryApi.php	97.36% <ø> (-0.20%)	:arrow_down:
src/InfluxDB2/InvocableScriptsApi.php	20.00% <20.00%> (ø)
src/InfluxDB2/Client.php	94.87% <100.00%> (+0.42%)	:arrow_up:
src/InfluxDB2/FluxCsvParser.php	100.00% <100.00%> (ø)
src/InfluxDB2/HealthApi.php	100.00% <0.00%> (ø)
src/InfluxDB2/DefaultApi.php	89.58% <0.00%> (+0.90%)	:arrow_up:

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