RFR: hg: use --template instead of ext.py for metadata [v2]

[Erik Helin]

> Hi all,
> 
> please review this patch that makes `HgRepository.commitMetadata` use `--template` instead of `ext.py` for generating
> the metadata.
> Testing:
> - [x] `make test` passes on Linux x64
> 
> Thanks,
> Erik

Erik Helin has updated the pull request incrementally with one additional commit since the last revision:

  actions: update to Ubuntu 20.04

-------------

Changes:
  - all: https://git.openjdk.java.net/skara/pull/739/files
  - new: https://git.openjdk.java.net/skara/pull/739/files/4b359a5a..f6db5f1a

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=739&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=739&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/skara/pull/739.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/739/head:pull/739

PR: https://git.openjdk.java.net/skara/pull/739