diff --git a/.github/workflows/checks.yml b/.github/workflows/checks.yml
index 71ad266..f033641 100644
--- a/.github/workflows/checks.yml
+++ b/.github/workflows/checks.yml
@@ -11,10 +11,10 @@ jobs:
     name: Code Checks
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Cache dependencies
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/.composer/cache/files
           key: dependencies-code-checks
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 8e5ffdb..acd88cf 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -9,17 +9,17 @@ jobs:
       fail-fast: true
       matrix:
         os: [ ubuntu-latest ]
-        php: [ 7.4, 8.0, 8.1 ]
+        php: [ 7.4, 8.0, 8.1, 8.2 ]
         dependency-version: [ prefer-lowest, prefer-stable ]
 
     name: P${{ matrix.php }} - ${{ matrix.dependency-version }} - ${{ matrix.os }}
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Cache dependencies
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/.composer/cache/files
           key: dependencies-php-${{ matrix.php }}-composer-${{ hashFiles('composer.json') }}
diff --git a/composer.json b/composer.json
index fa3184b..3255433 100644
--- a/composer.json
+++ b/composer.json
@@ -4,14 +4,14 @@
   "type": "library",
   "require": {
     "php": "^7.2|^8.0",
-    "guzzlehttp/guzzle": "^6.3|^7.0",
+    "guzzlehttp/guzzle": "^7.0",
     "promphp/prometheus_client_php": "^1.0|^2.0"
   },
   "require-dev": {
     "phpstan/extension-installer": "^1.0",
-    "phpstan/phpstan": "^1.5.4",
-    "phpstan/phpstan-phpunit": "^1.1.0",
-    "phpstan/phpstan-strict-rules": "^1.1.0",
+    "phpstan/phpstan": "^1.5",
+    "phpstan/phpstan-phpunit": "^1.1",
+    "phpstan/phpstan-strict-rules": "^1.1",
     "phpunit/phpunit": "^9.4",
     "squizlabs/php_codesniffer": "^3.6"
   },
@@ -31,5 +31,10 @@
     "psr-0": {
       "Test\\PrometheusPushGateway\\": "tests/"
     }
+  },
+  "config": {
+    "allow-plugins": {
+      "phpstan/extension-installer": true
+    }
   }
 }
diff --git a/src/PrometheusPushGateway/PushGateway.php b/src/PrometheusPushGateway/PushGateway.php
index a16cc89..f5ee4e5 100644
--- a/src/PrometheusPushGateway/PushGateway.php
+++ b/src/PrometheusPushGateway/PushGateway.php
@@ -13,9 +13,9 @@
 
 class PushGateway
 {
-    const HTTP_PUT = "PUT";
-    const HTTP_POST = "POST";
-    const HTTP_DELETE = "DELETE";
+    public const HTTP_PUT = "PUT";
+    public const HTTP_POST = "POST";
+    public const HTTP_DELETE = "DELETE";
     /**
      * @var string
      */
@@ -42,7 +42,7 @@ public function __construct(string $address, ?ClientInterface $client = null)
      * Uses HTTP PUT.
      * @param CollectorRegistry $collectorRegistry
      * @param string $job
-     * @param array<string> $groupingKey
+     * @param array<string,string> $groupingKey
      * @throws GuzzleException
      */
     public function push(CollectorRegistry $collectorRegistry, string $job, array $groupingKey = []): void
@@ -55,7 +55,7 @@ public function push(CollectorRegistry $collectorRegistry, string $job, array $g
      * Uses HTTP POST.
      * @param CollectorRegistry $collectorRegistry
      * @param string $job
-     * @param array<string> $groupingKey
+     * @param array<string,string> $groupingKey
      * @throws GuzzleException
      */
     public function pushAdd(CollectorRegistry $collectorRegistry, string $job, array $groupingKey = []): void
@@ -67,7 +67,7 @@ public function pushAdd(CollectorRegistry $collectorRegistry, string $job, array
      * Deletes metrics from the Push Gateway.
      * Uses HTTP POST.
      * @param string $job
-     * @param array<string> $groupingKey
+     * @param array<string,string> $groupingKey
      * @throws GuzzleException
      */
     public function delete(string $job, array $groupingKey = []): void
@@ -78,7 +78,7 @@ public function delete(string $job, array $groupingKey = []): void
     /**
      * @param CollectorRegistry|null $collectorRegistry
      * @param string $job
-     * @param array<string> $groupingKey
+     * @param array<string,string> $groupingKey
      * @param string $method
      * @throws GuzzleException
      */