Fix git tag name resource in CI pipeline

Prior to this commit, the git tag used for the GitHub release generation
was missing the "v" prefix.

Author: bclozel

ci/scripts/generate-changelog.sh

@@ -9,4 +9,4 @@ java -jar /github-changelog-generator.jar \
   ${version} generated-changelog/changelog.md
 
 echo ${version} > generated-changelog/version
-echo ${version} > generated-changelog/tag
+echo v${version} > generated-changelog/tag