Fix newly discovered Psalm issues

Addresses all the `RiskyTruthyFalsyComparison` issues surfaced by newer versions of Psalm.

Bumps dev deps

- Closes #43
- Closes #41

Signed-off-by: George Steel <[email protected]>

Author: gsteel

composer.json

@@ -38,9 +38,9 @@
     },
     "require-dev": {
         "laminas/laminas-coding-standard": "~2.5.0",
-        "phpunit/phpunit": "^10.4",
-        "psalm/plugin-phpunit": "^0.18.4",
-        "vimeo/psalm": "^5.16"
+        "phpunit/phpunit": "^10.5.36",
+        "psalm/plugin-phpunit": "^0.19.0",
+        "vimeo/psalm": "^5.26.1"
     },
     "suggest": {
         "laminas/laminas-cache": "To support Laminas\\XmlRpc\\Server\\Cache usage"