build: remove local rebase-pr script (#37055)

Remove the local rebase-pr script with a deprecation message
informing the user to instead perform rebases via ng-dev

PR Close #37055

scripts/github/rebase-pr

@@ -1,45 +1,7 @@
 #!/usr/bin/env bash
 
-set -u -e -o pipefail
+# TODO: Remove this deprecation warning after a reasonable period.
 
-BASEDIR=$(dirname "$0")
-
-if [ $# -eq 0 ]; then
-    echo "Rebase github PR onto a branch"
-    echo
-    echo "$0 branch_to_rebase_on PR_NUMBER"
-    echo
-    exit 0
-fi
-
-REBASE_ON="$1"
-PR_NO="$2"
-
-
-HEAD_LABEL=`curl -s https://api.github.com/repos/angular/angular/pulls/$PR_NO | node $BASEDIR/utils/json_extract.js head.label`
-echo $HEAD_LABEL
-IFS=':' read -r -a array <<< "$HEAD_LABEL"
-USER="${array[0]}"
-USER_GIT_URL="git@github.com:$USER/angular.git"
-BRANCH="${array[1]}"
-OLD_BRANCH=`git branch | grep \* | cut -d ' ' -f2`
-
-echo =====================================================
-echo Rebasing $USER_GIT_URL branch $BRANCH onto $REBASE_ON
-echo =====================================================
-
-git fetch $USER_GIT_URL $BRANCH
-git checkout FETCH_HEAD
-PUSH_CMD="git push $USER_GIT_URL HEAD:$BRANCH -f";
-RESTORE_CMD="git checkout $OLD_BRANCH"
-git rebase upstream/master
-if [ $? -eq 0 ]; then
-    $PUSH_CMD
-    $RESTORE_CMD
-else
-    echo ===========================
-    echo Git rebase failed. RECOVER WITH:
-    echo "       $PUSH_CMD"
-    echo "       $RESTORE_CMD"
-    echo ===========================
-fi
+echo "The rebase script has been replaced by the rebase script provided in ng-dev";
+echo "To run the rebase via ng-dev run the following command:"
+echo "  $ yarn -s ng-dev pr rebase <pr-number>"