Replace the cryptographic algorithm by SHA-2

The static code scanning analysis detected the usage of MD5 as part of [
MapDeploymentStateProviderFactory](https://github.com/keycloak/keycloak/blob/a6dd9dc0f1605ce0ac2b424df10e15a6eff6ff70/model/map/src/main/java/org/keycloak/models/map/deploymentState/MapDeploymentStateProviderFactory.java#L58-L58).

Even though we could not find any ways of exploiting the code, we should
avoid its usage considering that MD5 is not collision-resistant.

Resolves keycloak#11290

model/map/src/main/java/org/keycloak/models/map/deploymentState/MapDeploymentStateProviderFactory.java

@@ -55,7 +55,7 @@ public void init(Config.Scope config) {
             seed = SecretGenerator.getInstance().randomString(10);
         }
         try {
-            Version.RESOURCES_VERSION = Base64Url.encode(MessageDigest.getInstance("MD5")
+            Version.RESOURCES_VERSION = Base64Url.encode(MessageDigest.getInstance("SHA-256")
                     .digest((seed + new ModelVersion(Version.VERSION_KEYCLOAK).toString()).getBytes()))
                     .substring(0, 5);
         } catch (NoSuchAlgorithmException e) {