ci: add earthly target to update changelog

Earthfile

@@ -156,6 +156,18 @@ git-version:
   SAVE ARTIFACT /tmp/upend_version.txt version.txt
   RUN rm /tmp/upend_version.txt
 
+changelog:
+  FROM orhunp/git-cliff
+  COPY .git .git
+  RUN git-cliff -o CHANGELOG.md
+  SAVE ARTIFACT CHANGELOG.md
+
+update-changelog:
+  LOCALLY
+  COPY +changelog/CHANGELOG.md .
+  RUN git add CHANGELOG.md && git commit -m "Update CHANGELOG"
+  RUN --push git push
+
 base-rust:
   FROM rust:bookworm
   RUN rustup component add clippy