chore: regenerate README (#373)

This PR was generated using Autosynth. 🌈


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

```
2020-12-14 20:08:40,952 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-monitoring/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2020-12-14 20:08:41,937 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/d87be5ac-dc2c-4c71-a9a8-1de3cbd95853/targets

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-monitoring.git",
-        "sha": "1fefb028ce504ac892f58a17b6f57143050022da"
+        "sha": "590723e9ca62d30b0f4cabf5605ea4422f0e184b"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "352f25621c28d2fa0784984ea0ed5ea697aa1525"
+        "sha": "996775eca5fd934edac3c2ae34b80ff0395b1717"
       }
     }
   ]

README.md

@@ -46,11 +46,11 @@ If you are using Maven without BOM, add this to your dependencies:
 
 If you are using Gradle, add this to your dependencies
 ```Groovy
-compile 'com.google.cloud:google-cloud-monitoring:2.0.8'
+compile 'com.google.cloud:google-cloud-monitoring:2.0.9'
 ```
 If you are using SBT, add this to your dependencies
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-monitoring" % "2.0.8"
+libraryDependencies += "com.google.cloud" % "google-cloud-monitoring" % "2.0.9"
 ```
 
 ## Authentication