chore: regenerate README (#292)

This PR was generated using Autosynth. 🌈


<details><summary>Log from Synthtool</summary>

```
2020-12-09 23:37:42,284 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-spanner-jdbc/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2020-12-09 23:37:43,159 synthtool [DEBUG] > Wrote metadata to .github/readme/synth.metadata/synth.metadata.

```
</details>

Full log will be available here:
https://source.cloud.google.com/results/invocations/1366ec45-7bc4-4111-8b8c-3a6ccc88a0cf/targets

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

.github/readme/synth.metadata/synth.metadata

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-spanner-jdbc.git",
-        "sha": "0065a9b319b09e71bf285f85c33514442a163dea"
+        "sha": "9eea34c4206845a5e23b5b6ac78509497fd06069"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "c2de32114ec484aa708d32012d1fa8d75232daf5"
+        "sha": "352f25621c28d2fa0784984ea0ed5ea697aa1525"
       }
     }
   ]

README.md

@@ -126,6 +126,8 @@ Java 8 OSX | [![Kokoro CI][kokoro-badge-image-3]][kokoro-badge-link-3]
 Java 8 Windows | [![Kokoro CI][kokoro-badge-image-4]][kokoro-badge-link-4]
 Java 11 | [![Kokoro CI][kokoro-badge-image-5]][kokoro-badge-link-5]
 
+Java is a registered trademark of Oracle and/or its affiliates.
+
 [product-docs]: https://cloud.google.com/spanner/docs/use-oss-jdbc
 [javadocs]: https://googleapis.dev/java/google-cloud-spanner-jdbc/latest/index.html
 [kokoro-badge-image-1]: http://storage.googleapis.com/cloud-devrel-public/java/badges/java-spanner-jdbc/java7.svg