Added command to show merge commit information
feature #1 Added sha2pr command to show merge commit information (peterrehm)

Discussion
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The  command shows the merge commit information.

Usage:

php
./gh sha2pr 87f0ffc -u peterrehm -r test
Working on peterrehm/test
Found SHA in PR #1
Open PR in your default browser? [y/n] n

Tickets:
- none

Commits
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- d12c623 Added command to show merge commit information (peterrehm)