chore(CI): set LAKE_CACHE_DIR

Author: tydeu

.github/build.in.yml

@@ -11,6 +11,9 @@ env:
   # are valid by-products of the Mathlib build. Build artifacts fetched from Lake's cache do
   # not necessarily satisfy this property.
   LAKE_NO_CACHE: true
+  # Direct Lake to store its artifact cache in `.lake`.
+  # Prevents Lake from using a directory it may not have permissions to under landrun.
+  LAKE_CACHE_DIR: .lake/cache
 
 concurrency:
   # label each workflow run; only the latest with each label will run

.github/workflows/bors.yml

@@ -21,6 +21,9 @@ env:
   # are valid by-products of the Mathlib build. Build artifacts fetched from Lake's cache do
   # not necessarily satisfy this property.
   LAKE_NO_CACHE: true
+  # Direct Lake to store its artifact cache in `.lake`.
+  # Prevents Lake from using a directory it may not have permissions to under landrun.
+  LAKE_CACHE_DIR: .lake/cache
 
 concurrency:
   # label each workflow run; only the latest with each label will run

.github/workflows/build.yml

@@ -28,6 +28,9 @@ env:
   # are valid by-products of the Mathlib build. Build artifacts fetched from Lake's cache do
   # not necessarily satisfy this property.
   LAKE_NO_CACHE: true
+  # Direct Lake to store its artifact cache in `.lake`.
+  # Prevents Lake from using a directory it may not have permissions to under landrun.
+  LAKE_CACHE_DIR: .lake/cache
 
 concurrency:
   # label each workflow run; only the latest with each label will run

.github/workflows/build_fork.yml

@@ -25,6 +25,9 @@ env:
   # are valid by-products of the Mathlib build. Build artifacts fetched from Lake's cache do
   # not necessarily satisfy this property.
   LAKE_NO_CACHE: true
+  # Direct Lake to store its artifact cache in `.lake`.
+  # Prevents Lake from using a directory it may not have permissions to under landrun.
+  LAKE_CACHE_DIR: .lake/cache
 
 concurrency:
   # label each workflow run; only the latest with each label will run