scripts: remove github-merge.py

This script has been moved to the bitcoin-core/bitcoin-maintainer-tools repository,
after discussion in a core dev meeting. The rationale being that it is also useful to
other projects, and thus should be moved to a more general repository.

Meeting log: http://www.erisian.com.au/bitcoin-core-dev/log-2019-08-15.html
See also: bitcoin-core/bitcoin-maintainer-tools#28

Author: fanquake

contrib/README.md

@@ -3,10 +3,10 @@ Repository Tools
 
 ### [Developer tools](/contrib/devtools) ###
 Specific tools for developers working on this repository.
-Contains the script `github-merge.py` for merging GitHub pull requests securely and signing them using GPG.
+Additional tools, including the `github-merge.py` script, are available in the [maintainer-tools](https://github.com/bitcoin-core/bitcoin-maintainer-tools) repository.
 
 ### [Verify-Commits](/contrib/verify-commits) ###
-Tool to verify that every merge commit was signed by a developer using the above `github-merge.py` script.
+Tool to verify that every merge commit was signed by a developer using the `github-merge.py` script.
 
 ### [Linearize](/contrib/linearize) ###
 Construct a linear, no-fork, best version of the blockchain.

contrib/devtools/README.md

@@ -89,66 +89,6 @@ example:
 BUILDDIR=$PWD/build contrib/devtools/gen-manpages.sh
 ```
 
-github-merge.py
-===============
-
-A small script to automate merging pull-requests securely and sign them with GPG.
-
-For example:
-
-  ./github-merge.py 3077
-
-(in any git repository) will help you merge pull request #3077 for the
-bitcoin/bitcoin repository.
-
-What it does:
-* Fetch master and the pull request.
-* Locally construct a merge commit.
-* Show the diff that merge results in.
-* Ask you to verify the resulting source tree (so you can do a make
-check or whatever).
-* Ask you whether to GPG sign the merge commit.
-* Ask you whether to push the result upstream.
-
-This means that there are no potential race conditions (where a
-pullreq gets updated while you're reviewing it, but before you click
-merge), and when using GPG signatures, that even a compromised GitHub
-couldn't mess with the sources.
-
-Setup
----------
-Configuring the github-merge tool for the bitcoin repository is done in the following way:
-
-    git config githubmerge.repository bitcoin/bitcoin
-    git config githubmerge.testcmd "make -j4 check" (adapt to whatever you want to use for testing)
-    git config --global user.signingkey mykeyid
-
-Authentication (optional)
---------------------------
-
-The API request limit for unauthenticated requests is quite low, but the
-limit for authenticated requests is much higher. If you start running
-into rate limiting errors it can be useful to set an authentication token
-so that the script can authenticate requests.
-
-- First, go to [Personal access tokens](https://github.com/settings/tokens).
-- Click 'Generate new token'.
-- Fill in an arbitrary token description. No further privileges are needed.
-- Click the `Generate token` button at the bottom of the form.
-- Copy the generated token (should be a hexadecimal string)
-
-Then do:
-
-    git config --global user.ghtoken "pasted token"
-
-Create and verify timestamps of merge commits
----------------------------------------------
-To create or verify timestamps on the merge commits, install the OpenTimestamps
-client via `pip3 install opentimestamps-client`. Then, download the gpg wrapper
-`ots-git-gpg-wrapper.sh` and set it as git's `gpg.program`. See
-[the ots git integration documentation](https://github.com/opentimestamps/opentimestamps-client/blob/master/doc/git-integration.md#usage)
-for further details.
-
 optimize-pngs.py
 ================