add ubuntu test in github actions

.github/workflows/Ubuntu.yml

@@ -0,0 +1,14 @@
+name: PebbleStrict
+on: [push, pull_request]
+
+jobs:
+  PebbleStrict:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Install tools
+      run: sudo apt-get install -y socat
+    - name: Clone acmetest
+      run: cd .. && git clone https://github.com/acmesh-official/acmetest.git  && cp -r acme.sh acmetest/
+    - name: Run acmetest
+      run: cd ../acmetest && ./letest.sh