Fix 3.2 to 3.3 (#2520)

* to_3.3.md: composer update symfony/flex
* to_3.3.md: Use global latest_tag_3_3

(cherry picked from commit 5e324e5)

Author: adriendupuis

docs/update_and_migration/from_2.5/to_3.3.md

@@ -1,6 +1,5 @@
 ---
 target_version: '3.3'
-latest_tag: '3.3.24'
 ---
 
 # Update the app to v3.3
@@ -52,23 +51,23 @@ Merge the current skeleton into your project:
     ``` bash
     git remote add content-skeleton https://github.com/ibexa/content-skeleton.git
     git fetch content-skeleton --tags
-    git merge v[[= latest_tag =]] --allow-unrelated-histories
+    git merge v[[= latest_tag_3_3 =]] --allow-unrelated-histories
     ```
 
 === "Ibexa Experience"
 
     ``` bash
     git remote add experience-skeleton https://github.com/ibexa/experience-skeleton.git
     git fetch experience-skeleton --tags
-    git merge v[[= latest_tag =]] --allow-unrelated-histories
+    git merge v[[= latest_tag_3_3 =]] --allow-unrelated-histories
     ```
 
 === "Ibexa Commerce"
 
     ``` bash
     git remote add commerce-skeleton https://github.com/ibexa/commerce-skeleton.git
     git fetch commerce-skeleton --tags
-    git merge v[[= latest_tag =]] --allow-unrelated-histories
+    git merge v[[= latest_tag_3_3 =]] --allow-unrelated-histories
     ```
 
 This introduces changes from the relevant website skeleton and results in conflicts.
@@ -102,9 +101,10 @@ Resolve the conflicts in the following way:
 
 ### B. Update the app
 
-Run `composer update` to update the dependencies:
+Update Symfony Flex, then update the dependencies:
 
 ``` bash
+composer update symfony/flex --no-plugins --no-scripts
 composer update
 ```