chore: regenerate README (#451)

This PR was generated using Autosynth. 🌈


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

```
2021-02-19 17:57:46,966 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-containeranalysis/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-02-19 17:57:48,547 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/b4d92a19-9f43-4cd2-968c-780efb646d79/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-containeranalysis.git",
-        "sha": "dd9ea39c083ca7102e68b44c773c00f94850d98c"
+        "sha": "979b50a50903ba0836bd516d3f759da9d97cc048"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "f327d3b657a63ae4a8efd7f011a15eacae36b59c"
+        "sha": "6946fd71ae9215b0e7ae188f5057df765ee6d7d2"
       }
     }
   ]

README.md

@@ -38,7 +38,7 @@ If you are using Maven without BOM, add this to your dependencies:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-containeranalysis</artifactId>
-  <version>1.2.10</version>
+  <version>1.2.11</version>
 </dependency>
 
 ```