Support git SHA256 repos
Currently, trying to build Antora with a content source pointing to a git `SHA256` repo will fail with an error.
To initiate a git repo with `SHA256` you can run `git init --object-format=sha256`
```
❯ npx antora generate --stacktrace site.yml
[fetch] https://forge.fedoraproject.org/docs/site-frontpage.git [#####################################################]
[fetch] ...://forge.fedoraproject.org/docs/release-docs-home.git [#####################################################]
[fetch] https://forge.fedoraproject.org/docs/install-guide.git [#####################################################]
[fetch] https://forge.fedoraproject.org/docs/sysadmin-guide.git [#####################################################]
[fetch] ...ora/docs/fedora-linux-documentation/release-notes.git [#####################################################]
[fetch] https://forge.fedoraproject.org/docs/quick-docs.git [#####################################################]
[clone] https://forge.fedoraproject.org/commops/docs.git [?????????????????????????????????????????????????????]
[16:51:14.327] FATAL (antora): Could not find 6cf85deb74b57fbf903f323ee7be27adbe7f2d214c436c3a07517766033d5147 (url: https://forge.fedoraproject.org/commops/docs.git)
Cause: Error
at transformGitCloneError (/var/home/spytec/projects/docs-fp-o/node_modules/@antora/content-aggregator/lib/aggregate-content.js:1002:22)
at /var/home/spytec/projects/docs-fp-o/node_modules/@antora/content-aggregator/lib/aggregate-content.js:207:17
at async loadRepository (/var/home/spytec/projects/docs-fp-o/node_modules/@antora/content-aggregator/lib/aggregate-content.js:197:7)
at async gracefulPromiseAllWithLimit (/var/home/spytec/projects/docs-fp-o/node_modules/@antora/content-aggregator/lib/aggregate-content.js:1080:7)
at async Promise.all (index 0)
at async generateSite (/var/home/spytec/projects/docs-fp-o/node_modules/@antora/site-generator/lib/generate-site.js:23:5)
at async Command.parseAsync (/var/home/spytec/projects/docs-fp-o/node_modules/commander/lib/command.js:936:5)
Caused by: NotFoundError: Could not find 6cf85deb74b57fbf903f323ee7be27adbe7f2d214c436c3a07517766033d5147.
at GitRefManager.resolveAgainstMap (/var/home/spytec/projects/docs-fp-o/node_modules/isomorphic-git/index.cjs:2078:11)
at GitRefManager.resolveAgainstMap (/var/home/spytec/projects/docs-fp-o/node_modules/isomorphic-git/index.cjs:2069:30)
at _fetch (/var/home/spytec/projects/docs-fp-o/node_modules/isomorphic-git/index.cjs:7835:42)
at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
at async _clone (/var/home/spytec/projects/docs-fp-o/node_modules/isomorphic-git/index.cjs:8178:42)
at async Object.clone (/var/home/spytec/projects/docs-fp-o/node_modules/isomorphic-git/index.cjs:8301:12)
at async loadRepository (/var/home/spytec/projects/docs-fp-o/node_modules/@antora/content-aggregator/lib/aggregate-content.js:197:7)
at async gracefulPromiseAllWithLimit (/var/home/spytec/projects/docs-fp-o/node_modules/@antora/content-aggregator/lib/aggregate-content.js:1080:7)
at async Promise.all (index 0)
at async generateSite (/var/home/spytec/projects/docs-fp-o/node_modules/@antora/site-generator/lib/generate-site.js:23:5) {
caller: 'git.clone',
code: 'NotFoundError',
data: {
what: '6cf85deb74b57fbf903f323ee7be27adbe7f2d214c436c3a07517766033d5147'
}
}
```
Encountered while building [Fedora docs](https://forge.fedoraproject.org/docs/docs-fp-o) for two repos
- https://forge.fedoraproject.org/commops/docs.git
- https://forge.fedoraproject.org/mentored-projects/docs.git
issue