RFR: skara: add aliases for publish and proxy

[Erik Helin]

Hi all,

please review this small patch that aliases for `git-publish` and `git-proxy`
to `skara.gitconfig`.

Testing:
- Manual testing of `git publish` and `git proxy`

Thanks,
Erik

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Commit messages:
 - skara: add aliases for publish and proxy

Changes: https://git.openjdk.java.net/skara/pull/587/files
 Webrev: https://webrevs.openjdk.java.net/skara/587/webrev.00
  Stats: 5 lines in 2 files changed: 3 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/skara/pull/587.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/587/head:pull/587

PR: https://git.openjdk.java.net/skara/pull/587