Reset git commit timestamp

Put this in a bash file and run it.

 git filter-branch -f --env-filter \ 
   'if [ $GIT_COMMIT = 5a5fe3bafd3128a3aa6b2f4983b96fcc1287f027 ] 
   then 
     export GIT_AUTHOR_DATE="Sat Jul 1 19:01:20 2017" 
     export GIT_COMMITTER_DATE="Sat Jul 1 19:01:20 2017" 
   fi'