lib data model services: don't claim support on PHP < 7.4

The syntax of the library (at least test code) is no
longer PHP < 7.4. compatible. Cannot automatically test
the library code on obsolete PHP versions, so do not
claim support for these.
PHP 7.4 kept as it is the version used in the WMF
environment as of this writing.

Bug: T381168
Change-Id: I0ad03f3f7a1898cd6d59f7a011000ac3b5e7803a

.github/workflows/lint-and-test.yaml

@@ -8,7 +8,7 @@ jobs:
         runs-on: ubuntu-latest
         strategy:
             matrix:
-                php_version: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4' ]
+                php_version: [ '7.4', '8.0', '8.1', '8.2', '8.3', '8.4' ]
         steps:
             - uses: actions/checkout@v4
             - name: Setup PHP

composer.json

@@ -24,7 +24,7 @@
 		"irc": "irc://irc.libera.chat/wikidata"
 	},
 	"require": {
-		"php": ">=7.2",
+		"php": ">=7.4",
 		"wikibase/data-model": "~9.0|~8.0",
 		"data-values/data-values": "^3.1.0",
 		"diff/diff": "~3.2",