Add push to trunk workflow (#205)

Author: kaishin

.github/workflows/pod-trunk-push.yml

@@ -0,0 +1,22 @@
+name: Push to Trunk
+
+on:
+  push:
+    tags:
+      - "*"
+
+jobs:
+  build:
+    runs-on: macOS-latest
+
+    steps:
+      - uses: actions/checkout@v1
+
+      - name: Deploy to Cocoapods
+        run: |
+          set -eo pipefail
+          export LIB_VERSION=$(git describe --tags `git rev-list --tags --max-count=1`)
+          pod lib lint --allow-warnings
+          pod trunk push --allow-warnings
+        env:
+          COCOAPODS_TRUNK_TOKEN: ${{ secrets.COCOAPODS_TRUNK_TOKEN }}

Gifu.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name = "Gifu"
-  s.version = "3.4.1"
+  s.version = ENV['LIB_VERSION'] || "0.0.1"
   s.summary = "High-performance animated GIF support for iOS "
   s.homepage = "https://github.com/kaishin/Gifu"
   s.social_media_url = "http://twitter.com/kaishin"