dockerfile: rename git hash and add git repo

- rename git hash to repo_GIT_HASH
- add arg for repo as well to provide customization
Signed-off-by: Lakshya Singh <lakshay.singh1108@gmail.com>

txood/Dockerfile

@@ -10,10 +10,11 @@ RUN apk update && \
 
 RUN apk add cargo
 
-ARG GIT_HASH=528fa92e5def1b6cc19127f2242137bf6f13550d
-RUN git clone --recurse-submodules https://gitlab.com/lightning-signer/txoo.git && \
+ARG TXOO_GIT_HASH=528fa92e5def1b6cc19127f2242137bf6f13550d
+ARG TXOO_REPO=https://gitlab.com/lightning-signer/txoo.git
+RUN git clone --recurse-submodules $TXOO_REPO && \
     cd txoo && \
-    git checkout $GIT_HASH && \
+    git checkout $TXOO_GIT_HASH && \
     cargo build --release -p txood
 
 # txoo runner