feat: add logs of lake and lean version (#24)

Elan installation now:
- reports the lake version
- reports the lean version

resolves #12

scripts/detect_mathlib.sh

@@ -14,6 +14,7 @@ if grep -q "$dot_lean_pattern" lakefile.lean || grep -Pzq "$dot_toml_pattern" la
   echo "DETECTED_MATHLIB=true" >> "$GITHUB_OUTPUT"
   echo "Project is downstream of Mathlib. Using Mathlib cache."
 else
+  echo "DETECTED_MATHLIB=false" >> "$GITHUB_OUTPUT"
   echo "Project is not downstream of Mathlib. Skipping Mathlib cache."
 fi
 

scripts/install_elan.sh

@@ -7,5 +7,7 @@ set -o pipefail
 curl -sSfL https://github.com/leanprover/elan/releases/download/v1.4.2/elan-x86_64-unknown-linux-gnu.tar.gz | tar xz
 ./elan-init -y --default-toolchain none
 echo "$HOME/.elan/bin" >> "$GITHUB_PATH"
+"$HOME"/.elan/bin/lean --version          
+"$HOME"/.elan/bin/lake --version
 
 echo "::endgroup::"