Bump proto-plus from 1.19.0 to 1.19.5

Bumps [proto-plus](https://github.com/googleapis/proto-plus-python) from 1.19.0 to 1.19.5.
- [Release notes](https://github.com/googleapis/proto-plus-python/releases)
- [Changelog](https://github.com/googleapis/proto-plus-python/blob/master/CHANGELOG.md)
- [Commits](googleapis/proto-plus-python@v1.19.0...v1.19.5)

---
updated-dependencies:
- dependency-name: proto-plus
  dependency-type: indirect
  update-type: version-update:semver-patch
...

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

requirements/main.txt

@@ -698,9 +698,9 @@ premailer==3.10.0 \
     --hash=sha256:021b8196364d7df96d04f9ade51b794d0b77bcc19e998321c515633a2273be1a \
     --hash=sha256:d1875a8411f5dc92b53ef9f193db6c0f879dc378d618e0ad292723e388bfe4c2
     # via -r requirements/main.in
-proto-plus==1.19.0 \
-    --hash=sha256:ce6695ce804383ad6f392c4bb1874c323896290a1f656560de36416ba832d91e \
-    --hash=sha256:df7c71c08dc06403bdb0fba58cf9bf5f217198f6488c26b768f81e03a738c059
+proto-plus==1.19.5 \
+    --hash=sha256:ae34ba29c9a2759b3b7c93b0d51d8c2d72933b92a7385820e9248d1975cf7508 \
+    --hash=sha256:f64036ae34d74f8c036aec0e135891ccaa0fe70c9e7413d0f465e5a573fc64a1
     # via google-cloud-bigquery
 protobuf==3.17.3 \
     --hash=sha256:13ee7be3c2d9a5d2b42a1030976f760f28755fcf5863c55b1460fd205e6cd637 \