ci: set umask 022 to prevent group-writable cache dirs (sr.ht default umask creates 0775 dirs)

ober

e92d7be24f566cf9fe2f27dcd6c2d79bfc5a5b66

diff --git a/.build.yml b/.build.yml
index 4542fbd..e434825 100644
--- a/.build.yml
+++ b/.build.yml
@@ -19,6 +19,7 @@ artifacts:
   - jerboa-gitsafe/jerboa-gitsafe-0.1.0.jpkg
 tasks:
   - build-jerboa-tools: |
+      umask 022
       cd jerboa
       sudo fallocate -l 4G /swapfile && sudo chmod 600 /swapfile && sudo mkswap /swapfile && sudo swapon /swapfile
       export CARGO_BUILD_JOBS=1