chore: regenerate README (#368)

This PR was generated using Autosynth. 🌈


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

```
2021-08-27 22:09:46,725 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-grafeas/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-08-27 22:09:47,956 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/a6acbeaa-bc90-4c98-9631-fb4dffefa96c/targets

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-grafeas.git",
-        "sha": "eb79e48f0c108225ac15aa9c74d643a1760d9e51"
+        "sha": "d8bec409483005016d20c95cad5d51dfe2405fdb"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "31728d872f50e439ded2f67fa8d67955b26a4e35"
+        "sha": "e770c12f2a9a5f84566fe04b16a4ceec1c8c109b"
       }
     }
   ]

README.md

@@ -26,7 +26,7 @@ If you are using Maven, add this to your pom.xml file:
 If you are using Gradle without BOM, add this to your dependencies
 
 ```Groovy
-compile 'io.grafeas:grafeas:2.0.1'
+implementation 'io.grafeas:grafeas:2.0.1'
 ```
 
 If you are using SBT, add this to your dependencies