chore: remove java 7 units check (#498)

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Source-Link: googleapis/synthtool@1a2878d

.github/workflows/ci.yaml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [7, 8, 11]
+        java: [8, 11]
     steps:
     - uses: actions/checkout@v2
     - uses: actions/setup-java@v1

synth.metadata

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-core.git",
-        "sha": "e9615ea60b30dccfae2e5c4f9247e591dbfeb52f"
+        "sha": "91822485ff4b85d6ebff52682a74ee5d022b8655"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "5d3c52f5db664eee9026db76b5bcb466f3a09ca9"
+        "sha": "1a2878d6909dd10ca4e3c1b5943d6622e996054e"
       }
     }
   ],