chore(deps): bump obi1kenobi/cargo-semver-checks-action from 2.6 to 2.8 (open-telemetry#3050)

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/semver.yml

@@ -26,4 +26,4 @@ jobs:
           toolchain: stable
           components: rustfmt
       - name: cargo-semver-checks
-        uses: obi1kenobi/cargo-semver-checks-action@7272cc2caa468d3e009a2b0a9cc366839348237b # v2.6
+        uses: obi1kenobi/cargo-semver-checks-action@5b298c9520f7096a4683c0bd981a7ac5a7e249ae # v2.8