[#26] ci: Revive automatic database updates

Database updates were broken for a while (and noone noticed because CI was
not even switched on). This commit:

- Adds some greyhat web scraping (fake User-Agent to avoid HTTP 403)
- Surfaces errors in intermediate recipe steps (`cmd && cmd` instead of
  `cmd; cmd`)
- Works around other possible CI errors in automatic PRs (--signoff)

Signed-off-by: Vitaliy Potyarkin <v.potyarkin@yadro.com>

.forgejo/workflows/updatechecker.yml

@@ -1,17 +1,19 @@
 on:
   schedule:
     - cron: "2 0 1 * *"
+  workflow_dispatch:
+
 jobs:
   checkupdates:
     runs-on: docker
     steps:
       - uses: actions/checkout@v3
-      - run: make update
+      - run: make clean_data update
       - run: |
           git config user.name "Snegurochka"
           git config user.email "snegurochka@frostfs.info"
           git switch -c update-dbs
           git add .
           git remote set-url origin https://x-access-token:${{ secrets.GITHUB_TOKEN }}@git.frostfs.info/TrueCloudLab/frostfs-locode-db
-          git commit -m "Automatic database update (UN/LOCODE version $(cat tmp/locode-version.txt))" && \
+          git commit -sm "Automatic database update (UN/LOCODE version $(cat tmp/locode-version.txt))" && \
           git push origin HEAD:refs/for/master -o topic=automatic-database-update

Makefile

@@ -71,8 +71,11 @@ data/countries.dat.gz: $(DIRS)
 # See https://unece.org/trade/cefact/UNLOCODE-Download
 tmp/locode.csv.zip :$(DIRS)
 	DOWNLOADURL=$$(wget -O - https://unece.org/trade/cefact/UNLOCODE-Download \
-		| grep -oP '(?<=href=")\S+loc\d+csv\.zip'); \
-	echo "$$DOWNLOADURL" | grep -oP '(?<=loc)\d+' > tmp/locode-version.txt; \
+		--header='User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:136.0) Gecko/20100101 Firefox/136.0' \
+		| grep -oP '(?<=href=")\S+loc\d+csv\.zip' \
+		| head -n1) && \
+	test -n "$$DOWNLOADURL" && \
+	echo "$$DOWNLOADURL" | grep -oP '(?<=loc)\d+' > tmp/locode-version.txt && \
 	wget -c "$$DOWNLOADURL" -O tmp/locode.csv.zip
 
 data/unlocode-SubdivisionCodes.csv.gz: tmp/locode.csv.zip