Updating version.json to: 26-dev (#14425)

Closes #14425

COPYBARA_INTEGRATE_REVIEW=https://github.com/protocolbuffers/protobuf/pull/14425 from protocolbuffers:main-202310162054 7e95b7fe8e
PiperOrigin-RevId: 573930599

version.json

@@ -1,17 +1,17 @@
 {
     "main": {
-        "protoc_version": "25-dev",
+        "protoc_version": "26-dev",
         "lts": false,
-        "date": "2023-07-11",
+        "date": "2023-10-16",
         "languages": {
-            "cpp": "4.25-dev",
-            "csharp": "3.25-dev",
-            "java": "3.25-dev",
-            "javascript": "3.25-dev",
-            "objectivec": "3.25-dev",
-            "php": "3.25-dev",
-            "python": "4.25-dev",
-            "ruby": "3.25-dev"
+            "cpp": "4.26-dev",
+            "csharp": "3.26-dev",
+            "java": "3.26-dev",
+            "javascript": "3.26-dev",
+            "objectivec": "3.26-dev",
+            "php": "3.26-dev",
+            "python": "4.26-dev",
+            "ruby": "3.26-dev"
         }
     }
 }