Add pg 18 to ci.yml

Author: adept

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
   build:
     strategy:
       matrix:
-        pg: [17, 16, 15, 14, 13, 12, 11, 10]
+        pg: [18, 17, 16, 15, 14, 13, 12, 11, 10]
     name: 🐘 PostgreSQL ${{ matrix.pg }}
     runs-on: ubuntu-latest
     container: pgxn/pgxn-tools