Fix permissions and ownership for .ssh

Author: adidenko

Dockerfile

@@ -7,7 +7,8 @@ FROM alpine:3.21
 RUN apk add --no-cache git github-cli bash \
     && adduser -u 1100 -s /sbin/nologin -D git \
     && mkdir -p /home/git/.ssh \
-    && chown 1100:1100 /home/git/.ssh
+    && chown 1100:1100 /home/git/.ssh \
+    && chmod 700 /home/git/.ssh
 
 ADD files/known_hosts /home/git/.ssh/known_hosts