Problem: hard to understand what changed recently

Solution: write up release notes

RELEASE_NOTES.md

@@ -0,0 +1,20 @@
+# 0.2.1
+
+This release contains a number of bugfixes and a change in handling gas price.
+It is no longer set statically but rather dynamically using an external oracle
+(see [config example](examples/config.toml))
+
+# 0.2.0
+
+This release, most notably, fixes a condition in which not all logs might be
+retrieved from an RPC endpoint, resulting in the bridge not being able to
+see all relevant events.
+
+It also improves the performance by introducing concurrent transaction batching.
+
+On the operations side, it'll now print the context of an occurring error
+before exiting to help investigating that error.
+
+# 0.1.0
+
+Initial release