GH-workflow: avoid redundant ci tests runs

- don't test dependabot PRs twice as push and pull
- don't run tests on changes in md files

Change-Id: I2cf5f333c1ec7913b379b739ab5c5a9da3e591e4
diff --git a/.github/workflows/ci_test.yml b/.github/workflows/ci_test.yml
index 42ec057..7fd2b30 100644
--- a/.github/workflows/ci_test.yml
+++ b/.github/workflows/ci_test.yml
@@ -1,6 +1,12 @@
 name: CI Test
 
-on: [push, pull_request]
+on:
+  push:
+    branches-ignore:
+      - 'dependabot/**'
+  pull_request:
+    paths-ignore:
+      - '**.md'
 
 jobs:
   build: