update base image to ubuntu:latest

[PabstMirror]

No description provided.

[jonpas]

Step 7/10 : RUN cd /tmp/armake && make install     && chmod +x /tmp/armake/bin/armake
 ---> Running in 7ae4a8f6ac4e
Makefile:21: *** missing separator.  Stop.
ERROR: Service 'latest' failed to build: The command '/bin/sh -c cd /tmp/armake && make install     && chmod +x /tmp/armake/bin/armake' returned a non-zero code: 2