Upgrade bunch of EOL docker images to Ubuntu 18.04

Author: mati865

ci/docker/aarch64-unknown-linux-musl/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:17.10
+FROM ubuntu:18.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
   gcc make libc6-dev git curl ca-certificates \

ci/docker/arm-unknown-linux-musleabihf/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:17.10
+FROM ubuntu:18.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
   gcc make libc6-dev git curl ca-certificates \

ci/docker/i686-unknown-linux-musl/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:17.10
+FROM ubuntu:18.04
 
 RUN dpkg --add-architecture i386
 RUN apt-get update

ci/docker/mips-unknown-linux-musl/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:17.10
+FROM ubuntu:18.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
         gcc libc6-dev qemu-user ca-certificates qemu-system-mips curl \

ci/docker/mipsel-unknown-linux-musl/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:17.10
+FROM ubuntu:18.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
         gcc libc6-dev qemu-user ca-certificates qemu-system-mips curl \

ci/docker/powerpc-unknown-linux-gnu/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:17.10
+FROM ubuntu:18.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
         gcc libc6-dev qemu-user ca-certificates \
@@ -7,4 +7,5 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 
 ENV CARGO_TARGET_POWERPC_UNKNOWN_LINUX_GNU_LINKER=powerpc-linux-gnu-gcc \
     CARGO_TARGET_POWERPC_UNKNOWN_LINUX_GNU_RUNNER="qemu-ppc -L /usr/powerpc-linux-gnu" \
+    CC=powerpc-linux-gnu-gcc \
     PATH=$PATH:/rust/bin

ci/docker/powerpc64-unknown-linux-gnu/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:17.10
+FROM ubuntu:18.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
         gcc libc6-dev qemu-user ca-certificates \

ci/docker/powerpc64le-unknown-linux-gnu/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:17.10
+FROM ubuntu:18.04
 
 RUN apt-get update && apt-get install -y --no-install-recommends \
         gcc libc6-dev qemu-user ca-certificates \

ci/docker/x86_64-unknown-linux-musl/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:17.10
+FROM ubuntu:18.04
 
 RUN apt-get update
 RUN apt-get install -y --no-install-recommends \