Fix empty continuation lines.

Dockerfile

@@ -2,18 +2,18 @@ FROM python:3.7-alpine
 
 RUN apk add --no-cache --virtual .build-deps \
         git make gcc musl-dev asciidoc \
-
+    \
     # Install deps
     && pip install snakeoil \
-
+    \
     # Clone catalyst repository
     && git clone https://anongit.gentoo.org/git/proj/catalyst.git catalyst \
-
+    \
     # Build and install catalyst
     && cd catalyst \
     && make \
     && python -m setup install \
-
+    \
     # Cleanup
     && cd .. \
     && rm -Rf catalyst \