Remove docker image caching, use devkitpro/dekitarm image from docker hub instead of an own installation

.travis.yml

@@ -1,24 +1,10 @@
 sudo: required
-
-before_cache:
-  # Save tagged docker images see https://github.com/travis-ci/travis-ci/issues/5358#issuecomment-248915326
-  - >
-    mkdir -p $HOME/docker && docker images -a --filter='dangling=false' --format '{{.Repository}}:{{.Tag}} {{.ID}}'
-    | grep 'wups-loader-builder'
-    | xargs -n 2 -t sh -c 'test -e $HOME/docker/$1.tar.gz || docker save $0 | gzip -2 > $HOME/docker/$1.tar.gz'
-
-cache:
-  bundler: true
-  directories:
-    - $HOME/docker
-
+branches:
+  only:
+   - master
 services:
 - docker
 
-before_install:
-  # Load cached docker images
-  - if [[ -d $HOME/docker ]]; then ls $HOME/docker/*.tar.gz | xargs -I {file} sh -c "zcat {file} | docker load"; fi
-
 addons:
   apt:
     packages:
@@ -55,5 +41,3 @@ deploy:
   file: WiiUPluginLoader_$versiontag.zip
   on:
     repo: Maschell/WiiUPluginLoader
-    tags: false
-    all_branches: true

Dockerfile

@@ -4,8 +4,8 @@ FROM wups/core:latest
 RUN rm -rf $DEVKITPRO/portlibs
 
 # Install devkitARM. Needed to build mocha.
-RUN yes | sudo dkp-pacman -Syu devkitARM --needed 
 ENV DEVKITARM=${DEVKITPRO}/devkitARM
+COPY --from=devkitpro/devkitarm $DEVKITARM $DEVKITARM
 
 # Get dependencies
 COPY --from=wiiulegacy/dynamic_libs:0.1 /artifacts $DEVKITPRO/portlibs