Bump pbr from 5.1.3 to 5.2.0 (#4918)

Bumps [pbr](https://docs.openstack.org/pbr/latest/) from 5.1.3 to 5.2.0.

Signed-off-by: dependabot[bot] <support@dependabot.com>

requirements/dev.txt

@@ -55,9 +55,9 @@ py==1.8.0 \
 
 # Required by mock
 funcsigs==1.0.2 --hash=sha256:330cc27ccbf7f1e992e69fef78261dc7c6569012cf397db8d3de0234e6c937ca
-pbr==5.1.3 \
-    --hash=sha256:8257baf496c8522437e8a6cfe0f15e00aedc6c0e0e7c9d55eeeeab31e0853843 \
-    --hash=sha256:8c361cc353d988e4f5b998555c88098b9d5964c2e11acf7b0d21925a66bb5824
+pbr==5.2.0 \
+    --hash=sha256:6901995b9b686cb90cceba67a0f6d4d14ae003cd59bc12beb61549bdfbe3bc89 \
+    --hash=sha256:d950c64aeea5456bbd147468382a5bb77fe692c13c9f00f0219814ce5b642755
 
 # Required by flake8
 entrypoints==0.3 --hash=sha256:589f874b313739ad35be6e0cd7efde2a4e9b6fea91edcc34e58ecbb8dbe56d19