[Backport 11.5] Major core upgrade needs info about other ext (#305)

* Major core upgrade needs info about other ext

The major core upgrade guide mentions to just do `composer req` on the core packages, which will fail in most cases, as there will be extensions blocking this, thus it should be mentioned how to cope with this error by just adapting the command.
Additionally the `-W` parameter would make sense to make updates more robust.
Additionally the example cmd show use line-continuation at the line ends to allow copy and paste

* Update UpgradeCore.rst

Co-authored-by: jpmschuler <jpmschuler@users.noreply.github.com>
Co-authored-by: Tom Warwick <tom.warwick@typo3.org>

Documentation/Major/UpgradeCore.rst

@@ -44,14 +44,21 @@ Assuming that the packages below are installed locally, the following example wo
 
 .. code::
 
-   $ composer require "typo3/cms-adminpanel:^11.5" "typo3/cms-backend:^11.5"
-   "typo3/cms-belog:^11.5" "typo3/cms-beuser:^11.5" "typo3/cms-core:^11.5" "typo3/cms-dashboard:^11.5"
-   "typo3/cms-felogin:^11.5" "typo3/cms-filelist:^11.5" "typo3/cms-filemetadata:^11.5"
-   "typo3/cms-fluid:^11.5" "typo3/cms-form:^11.5" "typo3/cms-frontend:^11.5" "typo3/cms-info:^11.5"
-   "typo3/cms-install:^11.5" "typo3/cms-linkvalidator:^11.5" "typo3/cms-lowlevel:^11.5"
-   "typo3/cms-recordlist:^11.5" "typo3/cms-recycler:^11.5" "typo3/cms-rte-ckeditor:^11.5"
-   "typo3/cms-setup:^11.5" "typo3/cms-t3editor:^11.5" "typo3/cms-tstemplate:^11.5" "typo3/cms-viewpage:^11.5"
+   $ composer require --update-with-all-dependencies "typo3/cms-adminpanel:^11.5" \
+   "typo3/cms-backend:^11.5" "typo3/cms-belog:^11.5" "typo3/cms-beuser:^11.5" \
+   "typo3/cms-core:^11.5" "typo3/cms-dashboard:^11.5" "typo3/cms-felogin:^11.5" \
+   "typo3/cms-filelist:^11.5" "typo3/cms-filemetadata:^11.5" "typo3/cms-fluid:^11.5" \
+   "typo3/cms-form:^11.5" "typo3/cms-frontend:^11.5" "typo3/cms-info:^11.5" \
+   "typo3/cms-install:^11.5" "typo3/cms-linkvalidator:^11.5" "typo3/cms-lowlevel:^11.5" \
+   "typo3/cms-recordlist:^11.5" "typo3/cms-recycler:^11.5" "typo3/cms-rte-ckeditor:^11.5" \
+   "typo3/cms-setup:^11.5" "typo3/cms-t3editor:^11.5" "typo3/cms-tstemplate:^11.5" \
+   "typo3/cms-viewpage:^11.5"
 
+A typical TYPO3 installation is likely to have multiple third party extensions installed and running the above command can create dependency errors.
+
+For example, when upgrading from TYPO3 v10 LTS to 11 LTS an error can occur stating that `"helhum/typo3-console": "^6.7"` is only compatible with 10 LTS, with the new version `^7.1.2` supporting TYPO3 v11 LTS.
+
+For each of these dependency errors, add the version requirement `"helhum/typo3-console:^7.1.2"` to the end of your :bash:`composer require` string and retry the command.
 
 Monitoring changes to TYPO3's core
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