chore(Dockerfile): streamline repo cloning with GitHub CLI

Author: oleander

Dockerfile

@@ -44,16 +44,14 @@ COPY .git /source/.git
 # Clone from local source into working directory
 WORKDIR /app
 
-RUN git clone --branch main /source /app --local
-RUN git remote set-url origin https://github.com/oleander/git-ai.git
-RUN git pull origin main
+ARG GH_TOKEN
+ENV GH_TOKEN=$GH_TOKEN
+RUN gh repo clone oleander/git-ai /app
 RUN cargo fetch
 RUN cargo build
 RUN cargo clippy
 
 ARG PR_NUMBER
-ARG GH_TOKEN
-ENV GH_TOKEN=$GH_TOKEN
 RUN gh pr checkout $PR_NUMBER
 RUN cargo fetch
 RUN cargo build