Merge ~xavpaice/charm-prometheus2:bug/1936895 into charm-prometheus2:master

[Xav Paice]

Pin python requests to support Python 3.5

In order to maintain Xenial support, we must use a version of requests
that still works with Python 3.5.

Resolves LP:#1936895

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

This merge proposal is being monitored by mergebot. Change the status to Approved to merge.

[🤖 prod-jenkaas-bootstack (prod-jenkaas-bootstack)]

A CI job is currently in progress. A follow up comment will be added when it completes.

[🤖 prod-jenkaas-bootstack (prod-jenkaas-bootstack)]

PASSED: Continuous integration, rev:2e8a2fd87cc8a10f08363e5194177f1ed267760e
https://jenkins.canonical.com/bootstack/job/lp-charm-prometheus2-ci/3/
Executed test runs:
    SUCCESS: https://jenkins.canonical.com/bootstack/job/lp-charm-test-unit/125/
    None: https://jenkins.canonical.com/bootstack/job/lp-update-mp/326/

Click here to trigger a rebuild:
https://jenkins.canonical.com/bootstack/job/lp-charm-prometheus2-ci/3//rebuild

review: Approve (continuous-integration)

[Paul Goins (vultaire)]

LGTM

review: Approve

[🤖 Canonical IS Merge Bot (canonical-is-mergebot)]

Change successfully merged at revision 72270a0ef541e066aac50a0f593264861e3b3270

diff --git a/src/wheelhouse.txt b/src/wheelhouse.txt
index f229360..842c8de 100644
--- a/src/wheelhouse.txt
+++ b/src/wheelhouse.txt
@@ -1 +1 @@
-requests
+requests<2.25.0