chore: check in backblaze bucket for existing files

.woodpecker/build.yaml

@@ -104,11 +104,12 @@ steps:
   - name: Check if files for R version already exist in s3
     environment:
       AWS_ACCESS_KEY_ID:
-        from_secret: AWS_ACCESS_KEY_ID
+        from_secret: B2_APPLICATION_KEY_ID
       AWS_SECRET_ACCESS_KEY:
-        from_secret: AWS_SECRET_ACCESS_KEY
-      AWS_REGION: eu-central-2
-    image: alpine:3.20
+        from_secret: B2_APPLICATION_KEY
+      AWS_REGION: s3.eu-central-003
+      AWS_ENDPOINT: s3.eu-central-003.backblazeb2.com
+    image: alpine:3.21
     commands:
       - apk add -q --no-cache aws-cli
       - aws s3 ls s3://devxy-r-builds/${PLATFORM_ID}/ | grep ${ARCH_ID} | tail -1 | awk '{print $NF}' | cut -c 3-7 > r_build_latest.txt
@@ -161,9 +162,9 @@ steps:
   #     region: eu-central-2
   #     # acl: public-read
   #     access_key:
-  #       from_secret: AWS_ACCESS_KEY_ID
+  #       from_secret: B2_APPLICATION_KEY_ID
   #     secret_key:
-  #       from_secret: AWS_SECRET_ACCESS_KEY
+  #       from_secret: B2_APPLICATION_KEY
   #     overwrite: false
   #   volumes:
   #     - ci-tmp-rwx:/tmp # agent on k8s