ci(java): ignore bot users for generate-files-bot (#1202)

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Synth log will be available here:
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Source-Link: googleapis/synthtool@3f67cee

.github/generated-files-bot.yml

@@ -5,3 +5,7 @@ externalManifests:
 - type: json
   file: '.github/readme/synth.metadata/synth.metadata'
   jsonpath: '$.generatedFiles[*]'
+ignoreAuthors:
+- 'renovate-bot'
+- 'yoshi-automation'
+- 'release-please[bot]'

synth.metadata

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/google-http-java-client.git",
-        "sha": "059ab361f790c59ff31cd2acdf2e6a5b86159b92"
+        "sha": "51168fdbb5f739a8851b85356d04b3a042699ccf"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "5d11bd2888c38ce1fb6fa6bf25494a4219a73928"
+        "sha": "3f67ceece7e797a5736a25488aae35405649b90b"
       }
     }
   ],