chore: regenerate README (#673)

This PR was generated using Autosynth. 🌈


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

```
2021-08-24 17:43:41,620 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-containeranalysis/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-08-24 17:43:42,744 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/30b62f21-8748-4329-9876-ad91d6c6a29c/targets

- [ ] To automatically regenerate this PR, check this box. (May take up to 24 hours.)

Author: yoshi-automation

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-containeranalysis.git",
-        "sha": "71209b3deb889a1cb6e3af81415091485a72f848"
+        "sha": "7035172bde34e3cadb61e84ff9a34d98aea10b5a"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "484b7ec7bdef3909589a83e3d763e7588cb8c37c"
+        "sha": "8032ab5a32471d85ece8fc261df16cc40fbfa4fb"
       }
     }
   ]

README.md

@@ -41,7 +41,7 @@ If you are using Maven without BOM, add this to your dependencies:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-containeranalysis</artifactId>
-  <version>2.1.0</version>
+  <version>2.1.1</version>
 </dependency>
 
 ```
@@ -56,13 +56,13 @@ compile 'com.google.cloud:google-cloud-containeranalysis'
 If you are using Gradle without BOM, add this to your dependencies
 
 ```Groovy
-compile 'com.google.cloud:google-cloud-containeranalysis:2.1.0'
+compile 'com.google.cloud:google-cloud-containeranalysis:2.1.1'
 ```
 
 If you are using SBT, add this to your dependencies
 
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-containeranalysis" % "2.1.0"
+libraryDependencies += "com.google.cloud" % "google-cloud-containeranalysis" % "2.1.1"
 ```
 
 ## Authentication