Fix CI config to check if branch is master before skipping (#9140)

Related to: https://github.com/influxdata/telegraf/pull/9076

In order to support skipping a job depending on file changes, only works on non-master branches. This pull requests updates the config to check the current branch.

.circleci/config.yml

@@ -27,11 +27,11 @@ executors:
 commands:
   check-changed-files-or-halt:
       steps:
-        - run: git diff master --name-only --no-color | egrep -e "^(\.circleci\/.*)|(.*\.(go|mod|sum))|Makefile$" || circleci step halt
+        - run: ./scripts/check-file-changes.sh
   check-changed-files-or-halt-windows:
       steps:
         - run: 
-            command: git diff master --name-only --no-color | egrep -e "^(\.circleci\/.*)|(.*\.(go|mod|sum))|Makefile$" || circleci step halt
+            command: ./scripts/check-file-changes.sh
             shell: bash.exe
   test-go:
     parameters:

scripts/check-file-changes.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+BRANCH="$(git rev-parse --abbrev-ref HEAD)"
+echo $BRANCH
+if [[ "$BRANCH" != "master" ]]; then
+    git diff master --name-only --no-color | egrep -e "^(\.circleci\/.*)|(.*\.(go|mod|sum))|Makefile$" || circleci step halt;
+fi