fix(update-aws-cdk): Ensure a valid git branch name

Remove invalid `^` character from branch name as described in the spec - https://git-scm.com/docs/git-check-ref-format.

See also #2698.

Author: akash1810

script/update-aws-cdk

@@ -51,7 +51,13 @@ raisePR() {
   AWSCDKLIB_VERSION=$(jq -r '.peerDependencies."aws-cdk-lib"' < "$ROOT_DIR/package.json")
   CONSTRUCT_VERSION=$(jq -r '.peerDependencies.constructs' < "$ROOT_DIR/package.json")
 
-  BRANCH_NAME="update-aws-cdk-$AWSCDK_VERSION"
+  BRANCH_NAME=$(
+    echo "update-aws-cdk-$AWSCDK_VERSION" \
+    | sed 's/\^//g' # Remove ^ to ensure a valid branch name. See https://git-scm.com/docs/git-check-ref-format.
+  )
+
+  echo $BRANCH_NAME
+
   COMMIT_SUBJECT="fix(deps): Update AWS CDK libraries to $AWSCDK_VERSION, and constructs to $CONSTRUCT_VERSION"
   COMMIT_BODY="Update aws-cdk to $AWSCDK_VERSION, aws-cdk-lib to $AWSCDKLIB_VERSION, constructs to $CONSTRUCT_VERSION"