Implement Xgit.Tag.from_object/1.

[scouten]

Changes in This Pull Request

Parse a tag structure from an Xgit.Object structure.

Checklist

• This PR represents a single feature, fix, or change.
• All applicable changes have been documented.
• There is test coverage for all changes.
• All cases where a literal value is returned use the cover macro to force code coverage.
• Any code ported from jgit maintains all existing copyright and license notices. n/a
• If new files are ported from jgit, the path to the corresponding file(s) is included in the header comment. n/a
• Any TO DO items (or similar) have been entered as GitHub issues and the link to that issue has been included in a comment. n/a

[codecov]

Codecov Report

Merging #270 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master   #270   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files          28     28           
  Lines        1358   1377   +19     
=====================================
+ Hits         1358   1377   +19

Impacted Files	Coverage Δ
lib/xgit/util/parse_header.ex	100% <ø> (ø)	⬆️
lib/xgit/tag.ex	100% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ed7d950...48dc127. Read the comment docs.