fix(cat-ci): Flutter broken CI cache (#318)

* fix(cat-ci): Flutter broken CI cache

* fix(cat-ci): spelling

* fix(cat-ci): really fix the spelling

earthly/flutter/Earthfile

@@ -21,9 +21,6 @@ flutter-src:
 flutter-base:
     FROM debian:bookworm-20240513-slim
 
-    # TODO(minikin): we invalidate cache here to get the latest packages.
-    RUN --no-cache
-
     RUN apt-get update --fix-missing
     RUN apt-get install -y apt-utils git curl gzip unzip bzip2 bash jq gpg lcov
 

earthly/flutter/installer/Earthfile

@@ -1,6 +1,13 @@
 VERSION 0.8
 
-ARG --global BASE_URL = "https://github.com/input-output-hk/catalyst-storage/raw/main/web-browsers"
+# cspell: words Rxxxx
+
+# DO NOT USE `main` branch.
+# When updating the artifacts, update them in `main` and then create a sequentially numbered branch from it called `Rxxxx`
+# Then replace that Release version number in the path below.
+# This ensures that the tools are properly cached, and will also be re-installed when the upstream artifact is updated.
+# If a branch is no longer used by CI, delete it.
+ARG --global BASE_URL = "https://github.com/input-output-hk/catalyst-storage/raw/R0001/web-browsers"
 
 #TODO(minikin): https://github.com/input-output-hk/catalyst-storage/issues/1