ci: chmod go-w ~/.cache before pkg commands (sr.ht cache is group-writable)

ober

cbe02da7902e08f651cdf76c21bea493a64bdeba

diff --git a/.builds/ci.yml b/.builds/ci.yml
index 74528f7..67447db 100644
--- a/.builds/ci.yml
+++ b/.builds/ci.yml
@@ -34,6 +34,7 @@ tasks:
 - package: |
     cd jerboa-qt
     J="$HOME/jerboa/dist/jerboa"
+    chmod -R go-w "$HOME/.cache"
     "$J" pkg verify
     "$J" pkg policy
     "$J" pkg build