Upgrade Alpine base (3.15.4 -> 3.16.0)

Upgrade Alpine base (3.15.0 -> 3.15.4)

Ensure /etc/exim/exim.conf permissions are what Exim will be happy with

Add Gitlab CI/CD integration

Supersedes devture#16

Upgrade Alpine base (3.14.3 -> 3.15.0)

Merge pull request devture#13 from sakkiii/patch-3

Security updated - Alpine Linux 3.14.3

Merge pull request devture#12 from sakkiii/patch-2

alpine: bump 3.14.2 for openssl security fixes

Merge pull request devture#11 from sakkiii/patch-2

Update alpine to 3.14.1 to fix CVE-2021-36159

Update Alpine base (3.13 -> 3.14)

Merge pull request devture#9 from marcquark/master

disable TLSv1.0 for real