build(deps): bump flyway/flyway in /db

Bumps flyway/flyway from 10.14.0-alpine to 10.20.0-alpine.

---
updated-dependencies:
- dependency-name: flyway/flyway
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

db/Dockerfile

@@ -1,3 +1,3 @@
-FROM flyway/flyway:10.14.0-alpine
+FROM flyway/flyway:10.20.0-alpine
 
 COPY ./patches/ /flyway/sql/