nginx: stable 1.12 to 1.18

[croensch]

The tag 'stable' is built from the 'nginx1' topic.

2020-03-15:
https://hub.docker.com/repository/registry-1.docker.io/croensch/amzn-nginx/builds/879b49e0-5885-4a7b-a62c-45b4bd55d3d5

Installing:
nginx x86_64 1:1.12.2-2.amzn2.0.2 amzn2extra-nginx1 533 k

2021-05-07:
https://hub.docker.com/repository/registry-1.docker.io/croensch/amzn-nginx/builds/c703ebdf-a176-4dcc-b8d9-1ed831e0d069

Installing:
nginx x86_64 1:1.18.0-1.amzn2.0.2 amzn2extra-nginx1 560 k

So for the 'nginx1' topic means we get a recent 'stable' (even-numbered) release. This is useful but emphasizes the need to rebuild/update the image more often.

• update the .conf files
• rename 'latest' to '1.16'
• alias 'stable' to 'latest'
• update the README.md

[croensch]

Sidenote: the DEPRECATED "amzn-nginx-php" was built on the EOL'd 'nginx1.12' topic.

2020-03-14:
https://hub.docker.com/repository/registry-1.docker.io/croensch/amzn-nginx-php/builds/8175e560-acf1-4ed5-9369-473dffc8714b

Installing:
nginx x86_64 1:1.12.2-2.amzn2.0.2 amzn2extra-nginx1.12 533 k

[croensch]

The tag 'latest' was built from the 'epel' topic.

2020-03-15:
https://hub.docker.com/repository/registry-1.docker.io/croensch/amzn-nginx/builds/d82d3df0-4520-430f-b2d9-157422945c08

Installing:
nginx x86_64 1:1.16.1-1.el7 epel 562 k

2021-05-04:

Installing:
nginx x86_64 1:1.16.1-3.el7 epel 563 k

As this did not change in so long we should rename it to '1.16' (and put 'latest' on 'stable').