Remove PHP <7.4 support

Undoing the changes in #70 is too annoying right now, and it's high time everyone stopped using PHP <7.4 anyway.

This is going to coincide with a major version bump.

.github/workflows/ci.yml

@@ -9,9 +9,9 @@ jobs:
     strategy:
       matrix:
         operating-system: ['ubuntu-latest']
-        php-versions: ['7.1', '7.2', '7.3', '7.4', '8.0', '8.1', '8.2']
+        php-versions: ['7.4', '8.0', '8.1', '8.2', '8.3']
 
-    continue-on-error: ${{ matrix.php-versions == '8.2' }}
+    continue-on-error: ${{ matrix.php-versions == '8.3' }}
 
     steps:
       - name: Checkout
@@ -26,11 +26,11 @@ jobs:
           coverage: none
 
       - name: Install Composer dependencies (PHP < 8.1)
-        if: ${{ matrix.php-versions != '8.2' }}
+        if: ${{ matrix.php-versions != '8.3' }}
         uses: "ramsey/composer-install@v1"
 
       - name: Install Composer dependencies - ignore-platform-reqs (PHP 8.1)
-        if: ${{ matrix.php-versions == '8.2' }}
+        if: ${{ matrix.php-versions == '8.3' }}
         uses: "ramsey/composer-install@v1"
         with:
           composer-options: --ignore-platform-reqs

composer.json

@@ -35,7 +35,7 @@
         }
     },
     "require": {
-        "php": "^7.1|^8",
+        "php": "^7.4|^8",
         "ext-json": "*",
         "paragonie/constant_time_encoding": "^2",
         "psr/http-message": "^1|^2",