Don't copy the license in.

Author: arokem

Dockerfile

@@ -193,5 +193,3 @@ LABEL org.label-schema.build-date=$BUILD_DATE \
       org.label-schema.vcs-url="https://github.com/nipreps/dmriprep" \
       org.label-schema.version=$VERSION \
       org.label-schema.schema-version="1.0"
-
-COPY license.txt /usr/local/license.txt