Document and explain the 4.1 requirement changes

And, more specifically, the changes needed for Travis, as
explained in the previous commit.

.travis.dist.yml

@@ -1,11 +1,14 @@
 language: php
 
 addons:
-  postgresql: "10"
+  postgresql: "12"
+  apt:
+    packages:
+      - postgresql-12
+      - postgresql-client-12
 
 services:
   - mysql
-  - postgresql
   - docker
 
 cache:
@@ -20,6 +23,7 @@ php:
 
 env:
  global:
+  - PGVER=12
   - MOODLE_BRANCH=MOODLE_311_STABLE
  matrix:
   - DB=pgsql

docs/CHANGELOG.md

@@ -12,6 +12,16 @@ The format of this change log follows the advice given at [Keep a CHANGELOG](htt
 ### Added
 - `moodle-plugin-ci install` now provides an option `--db-port` to define a custom database port.
 
+### Changed
+- Updated [gha.dist.yml](https://github.com/moodlehq/moodle-plugin-ci/blob/master/gha.dist.yml) and
+  [.travis.dist.yml](https://github.com/moodlehq/moodle-plugin-ci/blob/master/.travis.dist.yml)
+  (and documentation) to fulfil [Moodle 4.1 new requirements](https://tracker.moodle.org/browse/MDL-71747).
+- ACTION REQUIRED: Review existing integrations running tests against master (4.1dev). There are a few Moodle 4.1 new requirements:
+  - PHP 7.4 is required (instead of 7.3).
+  - PostgreSQL 12 is required (instead of 10). Pay special attention to the changes needed for this and Travis!
+  - MariaDB 10.4 is required (instead of 10.2.29).
+  - Oracle 19 is required (instead of 11.2).
+
 ## [3.3.0] - 2022-06-28
 ### Added
 - PHPUnit code coverage will now automatically fallback between `pcov` => `xdebug` => `phpdbg`, using the "best" one available in the system. Still, if needed to, any of them can be forced, given all their requirements are fulfilled, using the following new options of the 'phpunit' command: `--coverage-pcov`, `--coverage-xdebug` or `--coverage-phpdbg`.

docs/GHAFileExplained.md

@@ -31,7 +31,7 @@ jobs:
     # DB services you need for testing.
     services:
       postgres:
-        image: postgres:10
+        image: postgres:12
         env:
           POSTGRES_USER: 'postgres'
           POSTGRES_HOST_AUTH_METHOD: 'trust'

docs/TravisFileExplained.md

@@ -13,12 +13,15 @@ language: php
 
 # Installs the updated version of PostgreSQL and extra APT packages.
 addons:
-  postgresql: "10"
+  postgresql: "12"
+  apt:
+    packages:
+      - postgresql-12
+      - postgresql-client-12
 
 # Ensure DB and docker services are running.
 services:
   - mysql
-  - postgresql
   - docker
 
 # Cache Composer's and NPM's caches to speed up build times.
@@ -38,6 +41,11 @@ php:
 # This section sets up the environment variables for the build.
 env:
  global:
+# This line instructs moodle-plugin-ci the version of PostgreSQL being
+# used, because, for PG 11 and up, both the user and the port were
+# changed by Travis. With that variable, the tool will switch to
+# socketed connections instead of localhost ones.
+  - PGVER=12
 # This line determines which version branch of Moodle to test against.
   - MOODLE_BRANCH=MOODLE_311_STABLE
 # This matrix is used for testing against multiple databases.  So for

gha.dist.yml

@@ -8,7 +8,7 @@ jobs:
 
     services:
       postgres:
-        image: postgres:10
+        image: postgres:12
         env:
           POSTGRES_USER: 'postgres'
           POSTGRES_HOST_AUTH_METHOD: 'trust'