feat: resolve nightly to latest vX.Y.Z-<sha>-nightly release (#558)

* feat: resolve nightly to latest vX.Y.Z-<sha>-nightly release

Query GitHub releases API to resolve the 'nightly' version input to the
latest immutable nightly tag, replacing the moving 'nightly' tag that is
being removed for supply-chain hardening.

Refs goreleaser/goreleaser#6550

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* feat: keep legacy 'nightly' tag working during transition

Fall back to the moving 'nightly' tag when no immutable
vX.Y.Z-<sha>-nightly release is found, so the action keeps working
between this release and the goreleaser nightly switchover.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* test: assert isNightlyTag accepts legacy fallback

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: accept nightly tags without 'v' prefix

goreleaser-pro publishes nightly releases as e.g. 2.16.0-eaeb08c50-nightly
(no 'v' prefix). Make the nightly tag regex tolerate either form, and
split the integration tests so OSS asserts the legacy fallback while
Pro asserts the new <version>-<sha>-nightly format.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Revert "fix: accept nightly tags without 'v' prefix"

The missing 'v' prefix on the goreleaser-pro nightly was a release
mistake; new nightlies will keep the 'v' prefix.

This reverts commit 7673f7f.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* ci: pass GITHUB_TOKEN to tests

The new nightly resolution hits api.github.com/repos/.../releases,
which is rate-limited for unauthenticated requests.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: note GITHUB_TOKEN need for nightly resolution

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Signed-off-by: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.github/workflows/test.yml

@@ -39,6 +39,8 @@ jobs:
       -
         name: Test
         run: npm test
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       -
         name: Upload coverage
         uses: codecov/codecov-action@57e3a136b779b570ffcdbf80b3bdc90e7fab3de2 # v6.0.0