chore: regenerate README (#469)

This PR was generated using Autosynth. 🌈


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

```
2021-01-26 22:00:11,715 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-pubsublite/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-01-26 22:00:12,681 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/a2b32a1f-1a9b-413a-94f1-bc082ba37afc/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-pubsublite.git",
-        "sha": "f869cdebd0d749f619b72b3db9ce931529be0408"
+        "sha": "6642cc6eb7c25611ad4d59f93f4001d7de5ebb95"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "16ec872dd898d7de6e1822badfac32484b5d9031"
+        "sha": "50a5fa9ffd3b91d3a4fc0de78a1bda92894d4ffc"
       }
     }
   ]

README.md

@@ -20,7 +20,7 @@ If you are using Maven, add this to your pom.xml file:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-pubsublite</artifactId>
-  <version>0.7.0</version>
+  <version>0.8.0</version>
 </dependency>
 <dependency>
   <groupId>com.google.cloud</groupId>