maintenance: dependabot (#8)

closes #7

Author: Greg Bowler

.github/dependabot.yml

@@ -0,0 +1,12 @@
+version: 2
+updates:
+  - package-ecosystem: composer
+    directory: "/"
+    schedule:
+      interval: daily
+    open-pull-requests-limit: 10
+    ignore:
+      - dependency-name: phpunit/phpunit
+        update-types: ["version-update:semver-patch"]
+      - dependency-name: phpstan/phpstan
+        update-types: ["version-update:semver-patch"]

composer.json

@@ -9,8 +9,8 @@
 		"phpgt/promise": "^2.0"
 	},
 	"require-dev": {
-		"phpstan/phpstan": "v1.8.0",
-		"phpunit/phpunit": "v9.5.21"
+		"phpstan/phpstan": "^v1.8",
+		"phpunit/phpunit": "^v9.5"
 	},
 
 	"autoload": {