Merge pull request #35 from r3pek/master

Upgrade to alpine 3.12 to support TLS 1.3

docker/Dockerfile.linux.amd64

@@ -1,4 +1,4 @@
-FROM alpine:3.7
+FROM alpine:3.12
 RUN apk add --no-cache ca-certificates git git-lfs openssh curl perl
 
 ADD posix/* /usr/local/bin/

docker/Dockerfile.linux.arm

@@ -1,4 +1,4 @@
-FROM arm32v6/alpine:3.7
+FROM arm32v6/alpine:3.12
 RUN apk add --no-cache ca-certificates git git-lfs openssh curl perl
 
 ADD posix/* /usr/local/bin/

docker/Dockerfile.linux.arm6

@@ -1,4 +1,4 @@
-FROM arm32v6/alpine:3.7
+FROM arm32v6/alpine:3.12
 RUN apk add --no-cache ca-certificates git git-lfs openssh curl perl
 
 ADD posix/* /usr/local/bin/

docker/Dockerfile.linux.arm64

@@ -1,4 +1,4 @@
-FROM arm64v8/alpine:3.7
+FROM arm64v8/alpine:3.12
 RUN apk add --no-cache ca-certificates git git-lfs openssh curl perl
 
 ADD posix/* /usr/local/bin/

docker/Dockerfile.linux.arm7

@@ -1,4 +1,4 @@
-FROM arm32v6/alpine:3.7
+FROM arm32v6/alpine:3.12
 RUN apk add --no-cache ca-certificates git git-lfs openssh curl perl
 
 ADD posix/* /usr/local/bin/

docker/Dockerfile.linux.arm8

@@ -1,4 +1,4 @@
-FROM arm64v8/alpine:3.7
+FROM arm64v8/alpine:3.12
 RUN apk add --no-cache ca-certificates git git-lfs openssh curl perl
 
 ADD posix/* /usr/local/bin/