Update pbr to 5.1.2 (#534)

This PR updates [pbr](https://pypi.org/project/pbr) from **5.1.1** to **5.1.2**.



*The bot wasn't able to find a changelog for this release. [Got an idea?](https://github.com/pyupio/changelogs/issues/new)*

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/pbr
  - Homepage: https://docs.openstack.org/pbr/latest/
</details>

Author: pyup-bot

requirements.txt

@@ -310,9 +310,9 @@ chardet==3.0.4 \
 mock==2.0.0 \
     --hash=sha256:5ce3c71c5545b472da17b72268978914d0252980348636840bd34a00b5cc96c1 \
     --hash=sha256:b158b6df76edd239b8208d481dc46b6afd45a846b7812ff0ce58971cf5bc8bba
-pbr==5.1.1 \
-    --hash=sha256:f6d5b23f226a2ba58e14e49aa3b1bfaf814d0199144b95d78458212444de1387 \
-    --hash=sha256:f59d71442f9ece3dffc17bc36575768e1ee9967756e6b6535f0ee1f0054c3d68
+pbr==5.1.2 \
+    --hash=sha256:a7953f66e1f82e4b061f43096a4bcc058f7d3d41de9b94ac871770e8bdd831a2 \
+    --hash=sha256:d717573351cfe09f49df61906cd272abaa759b3e91744396b804965ff7bff38b
 wcwidth==0.1.7 \
     --hash=sha256:f4ebe71925af7b40a864553f761ed559b43544f8f71746c2d756c7fe788ade7c \
     --hash=sha256:3df37372226d6e63e1b1e1eda15c594bca98a22d33a23832a90998faa96bc65e