ci: add build testing against named-data PPA

Change-Id: I6175fc5c5cfdc4f7cde7ec0d43f6b4a417dec9c5
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 50cb6ef..2280aee 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,3 +14,5 @@
     uses: named-data/actions/.github/workflows/jenkins-script-ubuntu.yml@v1
   macOS:
     uses: named-data/actions/.github/workflows/jenkins-script-macos.yml@v1
+  PPA:
+    uses: named-data/actions/.github/workflows/ppa.yml@v1