set MySQL to 5.5.62 on PHP 7.4

[lucatume]

This change aligns slic with the minimum WordPress requirements of PHP 7.2 and MySQL 5.5.

Link to WP requirements

As a concession to the fact that slic is a StellarWP tool, the minimum PHP version supported by it is PHP 7.4.

This is treated like a minor breaking change since it's breaking by default, but can be controller setting either the SLIC_DB_IMAGE or SLIC_DB_NO_MIN environment variables.

I've tested this on my Mac, and it all works: slic goes up with the database and all things work.

Some CLI "tests":

Using PHP 7.4 and not specifying the db image:

 $ SLIC_PHP_VERSION=7.4 slic config | awk '/^  db:/,/^  redis:/' | grep -v "^  redis:"
  db:
    environment:
      MYSQL_DATABASE: test
      MYSQL_ROOT_PASSWORD: password
    healthcheck:
      test:
        - CMD-SHELL
        - mysqlshow -u root -ppassword test
      timeout: 3s
      interval: 1s
      retries: 30
      start_period: 5s
    image: mysql:5.5.62
    networks:
      slic: null
    platform: linux/amd64
    ports:
      - mode: ingress
        target: 3306
        published: "9906"
        protocol: tcp
    tmpfs:
      - /var/lib/mysql

Using PHP 7.4 and specifying an image:

$ SLIC_PHP_VERSION=7.4 SLIC_DB_IMAGE=some-image:1.2.3 slic config | awk '/^  db:/,/^  redis:/' | grep -v "^  redis:"
  db:
    environment:
      MYSQL_DATABASE: test
      MYSQL_ROOT_PASSWORD: password
    healthcheck:
      test:
        - CMD-SHELL
        - mysqlshow -u root -ppassword test
      timeout: 3s
      interval: 1s
      retries: 30
      start_period: 5s
    image: some-image:1.2.3
    networks:
      slic: null
    ports:
      - mode: ingress
        target: 3306
        published: "9906"
        protocol: tcp
    tmpfs:
      - /var/lib/mysql

Using PHP 7.4 and specifying no-min db image:

 $ SLIC_PHP_VERSION=7.4 SLIC_DB_NO_MIN=1 slic config | awk '/^  db:/,/^  redis:/' | grep -v "^  redis:"
  db:
    environment:
      MYSQL_DATABASE: test
      MYSQL_ROOT_PASSWORD: password
    healthcheck:
      test:
        - CMD-SHELL
        - mysqlshow -u root -ppassword test
      timeout: 3s
      interval: 1s
      retries: 30
      start_period: 5s
    image: mariadb:10.7.8
    networks:
      slic: null
    ports:
      - mode: ingress
        target: 3306
        published: "9906"
        protocol: tcp
    tmpfs:
      - /var/lib/mysql

Using a version of PHP gt 7.4:

$ slic php-version set 8.0 && slic config | awk '/^  db:/,/^  redis:/' | grep -v "^  redis:"
  db:
    environment:
      MYSQL_DATABASE: test
      MYSQL_ROOT_PASSWORD: password
    healthcheck:
      test:
        - CMD-SHELL
        - mysqlshow -u root -ppassword test
      timeout: 3s
      interval: 1s
      retries: 30
      start_period: 5s
    image: mariadb:10.7.8
    networks:
      slic: null
    ports:
      - mode: ingress
        target: 3306
        published: "9906"
        protocol: tcp
    tmpfs:
      - /var/lib/mysql

[defunctl]

I don't fully understand why we want to do this. Is it to just test the lowest version of things our plugins would run on?

Even then, it looks like MySQL 5.5.x usage is now at 6.7%: https://wordpress.org/about/stats/

Although we don't know the combination usage, with PHP 7.4 usage at 28% still, shouldn't we assume most of those users aren't running MySQL 5.5.5?

That makes me think we shouldn't default to it, but still allow developers to change to use it if they want to test it in their matrix.

[defunctl]

Any breaking change should be a major version to properly follow semver, e.g. 2.0.0

[defunctl]

Also, if you're running one PHP 7.4 project with 5.5.5 and switch to a project that should use MariaDB, does the slic use command automatically spin up the correct db container?