chore: Drop PHP 8.1 support

.github/workflows/CI.yml

@@ -19,7 +19,7 @@ jobs:
           - 6379/tcp
     strategy:
       matrix:
-        php: ['8.1', '8.2', '8.3', '8.4']
+        php: ['8.2', '8.3', '8.4']
         dependencies: ['--ignore-platform-req=php', '--prefer-lowest --prefer-stable --ignore-platform-req=php']
     steps:
       - name: Checkout
@@ -57,7 +57,7 @@ jobs:
         uses: actions/checkout@v4
       - uses: shivammathur/setup-php@2.32.0
         with:
-          php-version: '8.1'
+          php-version: '8.2'
           extensions: mbstring, redis, apcu
           ini-values: apc.enable_cli=1, zend.assertions=1
           coverage: pcov
@@ -78,7 +78,7 @@ jobs:
     runs-on: ubuntu-24.04
     strategy:
       matrix:
-        php: ['8.1', '8.2', '8.3', '8.4']
+        php: ['8.2', '8.3', '8.4']
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -107,7 +107,7 @@ jobs:
         uses: actions/checkout@v4
       - uses: shivammathur/setup-php@2.32.0
         with:
-          php-version: '8.1'
+          php-version: '8.2'
           extensions: mbstring, redis, apcu
           coverage: none
       - name: Install dependencies

composer.json

@@ -3,7 +3,7 @@
     "description": "Prometheus instrumentation library",
     "license": "Apache-2.0",
     "require": {
-        "php": "~8.1.0|~8.2.0|~8.3.0|~8.4.0",
+        "php": "~8.2.0|~8.3.0|~8.4.0",
         "ext-json": "*",
         "psr/http-client": "^1.0",
         "psr/http-factory": "^1.0",