fix(ci): Update Earthly to 0.8

Earthfile

@@ -1,25 +1,27 @@
-# Set the Earthly version to 0.7
+VERSION 0.8
+
+IMPORT github.com/input-output-hk/catalyst-ci/earthly/mdlint:fix/improve-rust-builder-sj AS mdlint
+IMPORT github.com/input-output-hk/catalyst-ci/earthly/cspell:fix/improve-rust-builder-sj AS cspell
 
-VERSION 0.7
 FROM debian:stable-slim
 
 # cspell: words livedocs sitedocs
 
-# check-markdown markdown check using catalyst-ci.
+# check-markdown : markdown check using catalyst-ci.
 check-markdown:
-    DO github.com/input-output-hk/catalyst-ci/earthly/mdlint:v2.7.0+CHECK
+    DO mdlint+CHECK
 
-# markdown-check-fix markdown check and fix using catalyst-ci.
+# markdown-check-fix : markdown check and fix using catalyst-ci.
 markdown-check-fix:
     LOCALLY
 
-    DO github.com/input-output-hk/catalyst-ci/earthly/mdlint:v2.7.0+MDLINT_LOCALLY --src=$(echo ${PWD}) --fix=--fix
+    DO mdlint+MDLINT_LOCALLY --src=$(echo ${PWD}) --fix=--fix
 
-# check-spelling Check spelling in this repo inside a container.
+# check-spelling : Check spelling in this repo inside a container.
 check-spelling:
-    DO github.com/input-output-hk/catalyst-ci/earthly/cspell:v2.7.0+CHECK
+    DO cspell+CHECK
 
-# check-spelling Check spelling in this repo inside a container.
+# spell-list-words : List words in a dictionary
 spell-list-words:
     FROM ghcr.io/streetsidesoftware/cspell:8.0.0
     WORKDIR /work
@@ -29,7 +31,7 @@ spell-list-words:
     RUN cspell-cli --words-only --unique "wasm/**" | sort -f
 
 
-
+# repo-docs : target to store the documentation from the root of the repo.
 repo-docs:
     # Create artifacts of extra files we embed inside the documentation when its built.
     FROM scratch