[indico-web] Image default python release is now Py3

[Andrea Veri <averi src gnome org>]

commit 46dd4bc0a1e706a388fac27e11bcf8c0851320cc
Author: Andrea Veri <av gnome org>
Date:   Tue Jun 29 14:56:14 2021 +0000

    Image default python release is now Py3

 static/Dockerfile | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/static/Dockerfile b/static/Dockerfile
index 1b02257..1b1f935 100644
--- a/static/Dockerfile
+++ b/static/Dockerfile
@@ -1,9 +1,11 @@
 FROM nginxinc/nginx-unprivileged:stable-alpine
 
 USER root
-RUN apk add --no-cache py-pip unzip
+RUN apk add --no-cache python2 unzip
 
-RUN mkdir /tmp/indico-pip && \
+RUN virtualenv -p /usr/bin/python2 /tmp/indico-venv && \
+    source /tmp/indico-venv/bin/activate && \
+    mkdir /tmp/indico-pip && \
     pip download --no-deps -d /tmp/indico-pip indico && \
     unzip /tmp/indico-pip/indico-*.whl -d /srv/ 'indico/web/static/*' && \
     rm -rf /tmp/indico-pip