build(java): use actions/github-script v3 tag rather than full semver (googleapis#539)

This PR was generated using Autosynth. 🌈

Synth log will be available here:
https://source.cloud.google.com/results/invocations/90c590d5-0563-47bf-bafc-d8333db6ebbb/targets

- [ ] To automatically regenerate this PR, check this box.

Source-Link: googleapis/synthtool@7fcc405

Author: yoshi-automation

.github/workflows/approve-readme.yaml

@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
     if: github.repository_owner == 'googleapis' && github.head_ref == 'autosynth-readme'
     steps:
-      - uses: actions/github-script@v3.0.0
+      - uses: actions/github-script@v3
         with:
           github-token: ${{secrets.YOSHI_APPROVER_TOKEN}}
           script: |

.github/workflows/auto-release.yaml

@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
     if: contains(github.head_ref, 'release-v')
     steps:
-    - uses: actions/github-script@v3.0.0
+    - uses: actions/github-script@v3
       with:
         github-token: ${{secrets.YOSHI_APPROVER_TOKEN}}
         debug: true

synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-bigtable.git",
-        "sha": "0b029774d171403f1770a0cb3b6e0f0a6904f1ef"
+        "sha": "5b954407b4d41653b9c8a859b15d77efc821aa2a"
       }
     },
     {
@@ -19,7 +19,7 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "7d652819519dfa24da9e14548232e4aaba71a11c"
+        "sha": "7fcc405a579d5d53a726ff3da1b7c8c08f0f2d58"
       }
     }
   ],