Use author instead of committer in changelog computations

Any commits created through the GitHub UI (e.g. commits created by
merging PRs) usually assign GitHub itself as the ccommitter. This is
expected behaviour, as the commit is applied by GitHub itself. However,
for the purposes of changelog creation, showing the author (e.g. the
person who clicked the merge button on the PR) is more useful.

scripts/build/Jenkins/Jenkinsfile

@@ -190,6 +190,7 @@ def CheckoutBootstrapScripts(String branchName) {
         doGenerateSubmoduleConfigurations: false,
         extensions: [
             [$class: 'PruneStaleBranch'],
+            [$class: 'AuthorInChangelog'],
             [$class: 'SparseCheckoutPaths', sparseCheckoutPaths: [
                 [ $class: 'SparseCheckoutPath', path: 'scripts/build/Jenkins/' ],
                 [ $class: 'SparseCheckoutPath', path: 'scripts/build/bootstrap/' ],
@@ -234,6 +235,7 @@ def CheckoutRepo(boolean disableSubmodules = false) {
             branches: scm.branches,
             extensions: [
                 [$class: 'PruneStaleBranch'],
+                [$class: 'AuthorInChangelog'],
                 [$class: 'SubmoduleOption', disableSubmodules: disableSubmodules, recursiveSubmodules: true],
                 [$class: 'CheckoutOption', timeout: 60]
             ],
@@ -339,7 +341,10 @@ def TestMetrics(Map pipelineConfig, String workspace, String branchName, String
             checkout scm: [
                 $class: 'GitSCM',
                 branches: [[name: '*/main']],
-                extensions: [[$class: 'RelativeTargetDirectory', relativeTargetDir: 'mars']],
+                extensions: [
+                    [$class: 'AuthorInChangelog'],
+                    [$class: 'RelativeTargetDirectory', relativeTargetDir: 'mars']
+                ],
                 userRemoteConfigs: [[url: "${env.MARS_REPO}", name: 'mars', credentialsId: "${env.GITHUB_USER}"]]
             ]
             withCredentials([usernamePassword(credentialsId: "${env.SERVICE_USER}", passwordVariable: 'apitoken', usernameVariable: 'username')]) {