Bumps alpine docker images to v1.14.1

docs/check.Dockerfile

@@ -1,5 +1,5 @@
 
-FROM alpine:3.13 as alpine
+FROM alpine:3.14.1 as alpine
 
 RUN apk --no-cache --no-progress add \
     libcurl \

docs/docs.Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:3.13
+FROM alpine:3.14.1
 
 ENV PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/root/.local/bin
 

exp.Dockerfile

@@ -38,7 +38,7 @@ COPY --from=webui /src/static/ /go/src/github.com/traefik/traefik/static/
 RUN ./script/make.sh generate binary
 
 ## IMAGE
-FROM alpine:3.10
+FROM alpine:3.14.1
 
 RUN apk --no-cache --no-progress add bash curl ca-certificates tzdata \
     && update-ca-certificates \