Make volunteer translators aware of string-freeze.

CURA-11771

README.md

@@ -26,7 +26,9 @@
 *With hundreds of settings & community-managed print profiles,* <br>
 *Ultimaker Cura is sure to lead your next project to a success.*
 
-<br>
+**Contribute Printer Profiles?** -- Please [look here](https://github.com/Ultimaker/Cura/wiki/Adding-new-machine-profiles-to-Cura) first. <br>
+**Contribute Translations?** -- Please [look here](https://github.com/Ultimaker/Cura/wiki/Translating-Cura) first.
+
 <br>
 
 [![Button Building]][Building]   

resources/i18n/README.md

@@ -0,0 +1,5 @@
+If you aim to contribute translations please [look here](https://github.com/Ultimaker/Cura/wiki/Translating-Cura) first.
+
+In particular, take heed of the following: <br>
+When we're in the release-window (so that's when we have the beta out for the next Cura, but not the final release yet), we're also in the process of updating translations.
+_**If you make a PR with updated or fixed translations within this timespan, it's likely that your additions/changes will be ignored in favour of the 'official' ones, due to how our process is set up.**_