chore: regenerate README (#500)

This PR was generated using Autosynth. 🌈


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

```
2021-04-03 00:10:19,490 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-containeranalysis/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-04-03 00:10:20,724 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/ea97fab4-07b6-4b03-8148-8158662c50ab/targets

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-containeranalysis.git",
-        "sha": "4c4cee80df1e34ad5cf10a4c419f57fbfcde5faf"
+        "sha": "2eea20db783b81de4f12dc9e776d28ee510e7a2b"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "79c8dd7ee768292f933012d3a69a5b4676404cda"
+        "sha": "ff39353f34a36e7643b86e97724e4027ab466dc6"
       }
     }
   ]

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>1.2.32</version>
+  <version>1.2.33</version>
 </dependency>
 
 ```
@@ -51,12 +51,12 @@ 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:1.2.32'
+compile 'com.google.cloud:google-cloud-containeranalysis:1.2.33'
 ```
 
 If you are using SBT, add this to your dependencies
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-containeranalysis" % "1.2.32"
+libraryDependencies += "com.google.cloud" % "google-cloud-containeranalysis" % "1.2.33"
 ```
 
 ## Authentication