runtimes/charliecloud: bump apk-tools version for test
-WORKDIR=$3
+WORKDIR=$4
MIRROR=http://dl-cdn.alpinelinux.org/alpine/v3.6
- APK_TOOLS=apk-tools-static-2.7.5-r0.apk
+ APK_TOOLS=apk-tools-static-2.7.6-r0.apk
IMG="$WORKDIR/img"
## Bootstrap base Alpine Linux.
