Container build failure re ssl libraries

Container builds are failing on step 4:
```
Step 4/19 : RUN apk --update add build-base ruby-dev libc-dev linux-headers openssl-dev postgresql-dev sqlite-dev
---> Running in 5b9ffa64c9ee
fetch http://dl-cdn.alpinelinux.org/alpine/v3.8/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.8/community/x86_64/APKINDEX.tar.gz
ERROR: unsatisfiable constraints:
openssl-dev-1.0.2p-r0:
conflicts:
libressl-dev-2.7.4-r0[pc:libcrypto=1.0.2p]
libressl-dev-2.7.4-r0[pc:libssl=1.0.2p]
libressl-dev-2.7.4-r0[pc:openssl=1.0.2p]
satisfies: world[openssl-dev]
libressl-dev-2.7.4-r0:
conflicts:
openssl-dev-1.0.2p-r0[pc:libcrypto=2.7.4]
openssl-dev-1.0.2p-r0[pc:libssl=2.7.4]
openssl-dev-1.0.2p-r0[pc:openssl=2.7.4]
satisfies:
postgresql-dev-10.5-r0[libressl-dev]
ERROR: Service 'app' failed to build: The command '/bin/sh -c apk --update add build-base ruby-dev libc-dev linux-headers openssl-dev postgresql-dev sqlite-dev' returned a non-zero code: 3
```