readme: inform on the upper case variable

marcaurele · marcaurele · commit 9b7fcc2e0827 · 2021-02-14T12:15:43.000+01:00
Following PR prometheus#624 Signed-off-by: Marc-Aurèle Brothier <m@brothier.org>
diff --git a/README.md b/README.md
@@ -513,7 +513,7 @@ There's several steps to getting this working:
 
 **1. Gunicorn deployment**:
 
-The `prometheus_multiproc_dir` environment variable must be set to a directory
+The `PROMETHEUS_MULTIPROC_DIR` environment variable must be set to a directory
 that the client library can use for metrics. This directory must be wiped
 between Gunicorn runs (before startup is recommended).
 
