composer: restrict api-platform to <2.7.0 for now

It has multiple breaking changes and we can't easily support both for now,
so pin to a lower version until we upgrade.

CHANGELOG.md

+# v0.1.43
+
+* Temporarily restrict api-platform/core to < 2.7.0
+
 # v0.1.40
 
 * extension: add registerEntityManager() for registering doctrine entity managers

composer.json

@@ -7,7 +7,7 @@
         "php": "^7.3 || ^8.0",
         "ext-fileinfo": "*",
         "ext-json": "*",
-        "api-platform/core": "^2.6.6",
+        "api-platform/core": "^2.6.8 <2.7.0",
         "doctrine/annotations": "^1.0",
         "dragonmantank/cron-expression": "^3.1",
         "guzzlehttp/guzzle": "^7.0",

composer.lock

@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "ad20ed4b55d1d8cec3b4c5b4d13885d1",
+    "content-hash": "ad2ee3a5aa578024a91d663453371575",
     "packages": [
         {
             "name": "api-platform/core",