chore: add phpstan for static analysis (#406)

Author: bshaffer

.github/workflows/tests.yml

@@ -41,3 +41,17 @@ jobs:
           composer require friendsofphp/php-cs-fixer
           vendor/bin/php-cs-fixer fix --diff --dry-run .
           vendor/bin/php-cs-fixer fix --rules=native_function_invocation --allow-risky=yes --diff src
+
+  staticanalysis:
+    runs-on: ubuntu-latest
+    name: PHPStan Static Analysis
+    steps:
+    - uses: actions/checkout@v2
+    - name: Install PHP
+      uses: shivammathur/setup-php@v2
+      with:
+        php-version: '8.0'
+    - name: Run Script
+      run: |
+        composer global require phpstan/phpstan
+        ~/.composer/vendor/bin/phpstan analyse src

src/JWT.php

@@ -7,6 +7,7 @@
 use Exception;
 use InvalidArgumentException;
 use OpenSSLAsymmetricKey;
+use TypeError;
 use UnexpectedValueException;
 use DateTime;
 use stdClass;
@@ -229,6 +230,8 @@ public static function sign(string $msg, string|OpenSSLAsymmetricKey $key, strin
                     throw new DomainException($e->getMessage(), 0, $e);
                 }
         }
+
+        throw new DomainException('Algorithm not supported');
     }
 
     /**