Update variable naming (#7)

Co-authored-by: Nikolai Rodionov <nikolai.rodionov@grandcentrix.net>
Reviewed-on: https://git.badhouseplants.net/allanger/mkdocs-with-confluence/pulls/7

example/Dockerfile

@@ -9,9 +9,9 @@ RUN mkdir /out
 RUN mv $(find /src/dist -maxdepth 1 -mindepth 1 -name '*tar.gz') /out/mkdocs_with_confluence.tar.gz
 
 FROM BUILDER as common_builder
+ARG MKDOCS_TO_CONFLUENCE_PASSWORD
 ENV MKDOCS_TO_CONFLUENCE=true
-ARG JIRA_PASSWORD
-ENV JIRA_PASSWORD=$JIRA_PASSWORD
+ENV MKDOCS_TO_CONFLUENCE_PASSWORD=$MKDOCS_TO_CONFLUENCE_PASSWORD
 RUN pip install mkdocs mkdocs-material
 WORKDIR /src
 COPY ./example /src