chore: regenerate README (#184)

This PR was generated using Autosynth. 🌈


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

```
2021-08-11 00:14:20,459 synthtool [DEBUG] > Executing /root/.cache/synthtool/java-pubsublite-kafka/.github/readme/synth.py.
On branch autosynth-readme
nothing to commit, working tree clean
2021-08-11 00:14:21,674 synthtool [DEBUG] > Wrote metadata to .github/readme/synth.metadata/synth.metadata.

```
</details>

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

@@ -4,14 +4,14 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-pubsublite-kafka.git",
-        "sha": "f82a7c6ae88dddf68f71d51405d225581e968753"
+        "sha": "20ae0ba14d7623741b05825be240edcfc33f3974"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "5605f38f153e7627ba4441a2c5181060b664d224"
+        "sha": "6252f2cd074c38f37b44abe5e96d128733eb1b61"
       }
     }
   ]

README.md

@@ -72,6 +72,12 @@ be implemented using Pub/Sub Lite as a backend. The key differences are:
 - ProducerRecord may not specify partition explicitly.
 - Consumers may not dynamically create consumer groups (subscriptions).
 
+Note:
+- In order to use Pub/Sub Lite [seek operations](https://cloud.google.com/pubsub/lite/docs/seek),
+  Consumers must have auto-commit enabled. Consumer seek methods are client-initiated, whereas
+  Pub/Sub Lite seek operations are initiated out-of-band and pushed to Consumers. Both types of
+  seeks should not be used concurrently, as they would interfere with one another.
+
 
 
 #### Publishing messages