Add dependabot

and skip workflow run on pull request
triggered by dependabot because it's NPOTB

[skip ci]

Signed-off-by: nanake <nanake@users.noreply.github.com>

.github/dependabot.yml

@@ -0,0 +1,7 @@
+version: 2
+updates:
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"

.github/workflows/build.yml

@@ -2,6 +2,8 @@ name: Build FFmpeg
 
 on:
   push:
+    branches-ignore:
+      - 'dependabot/**'
     paths-ignore:
       - '**.md'
       - 'LICENSE'

.github/workflows/pr.yml

@@ -3,6 +3,8 @@ on:
   pull_request:
     branches:
       - master
+    branches-ignore:
+      - 'dependabot/**'
     paths-ignore:
       - '**.md'
       - 'LICENSE'