Update alpine/curl Docker tag to v8.12.0 (#329)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

Earthfile

@@ -127,7 +127,7 @@ explorer:
     SAVE IMAGE --push ${HARBOR_DOCKER_REGISTRY}/explorer:latest
 
 docs:
-    FROM alpine/curl:8.11.1
+    FROM alpine/curl:8.12.0
     WORKDIR /app
     COPY +build/generated generated