add librdkafka:1.7 to ci (#51)

Author: nick-zh

Diff for: .github/workflows/test.yml

@@ -13,8 +13,14 @@ jobs:
           matrix:
             include:
               - php: '8.0.0'
-                librdkafka: 'v1.6.1'
+                librdkafka: 'v1.7.0'
                 memcheck: '1'
+              - php: '8.0.0'
+                librdkafka: 'v1.7.0'
+              - php: '7.4.0'
+                librdkafka: 'v1.7.0'
+              - php: '7.3.0'
+                librdkafka: 'v1.7.0'
               - php: '8.0.0'
                 librdkafka: 'v1.6.1'
               - php: '7.4.0'