Documentation - Update Git version supported

Summary

• Git version (v1.8) stated in documentation (https://confluence.atlassian.com/display/BAMBOO/Supported+platforms) is inaccurate, causing issues in Bamboo server.

Overview

When running Automatic branch merging against a Git repository Bamboo:

• create a directory in <bamboo-home>/xml-data/build-dir/serverSide/PROJ-PLAN0-123/mergeWorkspace to be used by the merge event
• run a command that uses -c parameter

  git clone <bamboo-home>/xml-data/build-dir/_git-repositories-cache/b1a5506f772601076f7b53ae0c0dcb2f697cafc1 --shared --no-checkout '-c filter.lfs.smudge=' '-c filter.lfs.required=false' <bamboo-home>/xml-data/build-dir/serverSide/PROJ-PLAN0-123/mergeWorkspace
  

Issue

• Git version below 1.8.1.5 does not have -c parameter, in which causes failure in Bamboo

  2017-02-15 10:57:15,271 WARN [5-DelayedChangeDetectionThread:pool-11-thread-5] [ChainExecutionManagerImpl] Merge command error: fatal: Not a git repository (or any of the parent directories): .git
  2017-02-15 10:57:15,271 WARN [5-DelayedChangeDetectionThread:pool-11-thread-5] [ChainExecutionManagerImpl] Unable to merge PROJ-PLAN0-123 merge result: MergeResultSummaryImpl
  {integrationStrategy='GATE_KEEPER', mergeState='FAILED', pushState='TO_BE_ATTEMPTED', failureReason='Merge command error: fatal: Not a git repository (or any of the parent directories): .git', integrationBranchVcsKey='93623c155d66e0fa117bf10202ad9ef857f31990', mergeResultVcsKey='null', integrationRepositoryId=176390237, integrationRepositoryBranchName='foo', branchTargetVcsKey='0b0cb1c487fdb62d198b3bb9d9e54c42dd39cfe5', branchName='bar'}
  2017-02-15 10:57:15,272 ERROR [5-DelayedChangeDetectionThread:pool-11-thread-5] [ChainExecutionManagerImpl] Failed to merge for plan-result: PROJ-PLAN0-123. Merge command error: fatal: Not a git repository (or any of the parent directories): .git
  

Suggestion

• Update documentation https://confluence.atlassian.com/display/BAMBOO/Supported+platforms, replacing Git version 1.8 with 1.8.1.5 or above (in the Bamboo server)
• Update documentation https://confluence.atlassian.com/display/BAMBOO/Using+plan+branches, stating Limitations with plan branches >> Auto branch merging requires Git version 1.8.1.5 or above as capability (in the Bamboo server).