Bump minimum PyYAML to 3.13. (#14720)

PyYAML 3.13 fixes some issues with Python 3.7 compatibility
and was released in 2018.

2 files changed, 2 insertions, 1 deletions

diff --git a/changelog.d/14720.misc b/changelog.d/14720.misc
new file mode 100644

index 0000000000..0defc01550
--- /dev/null
+++ b/changelog.d/14720.misc
@@ -0,0 +1 @@
+Bump minimum PyYAML to 3.13.
diff --git a/pyproject.toml b/pyproject.toml

index 21bc11da88..3281441534 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -136,7 +136,7 @@ Twisted = {extras = ["tls"], version = ">=18.9.0"}
 treq = ">=15.1"
 # Twisted has required pyopenssl 16.0 since about Twisted 16.6.
 pyOpenSSL = ">=16.0.0"
-PyYAML = ">=3.11"
+PyYAML = ">=3.13"
 pyasn1 = ">=0.1.9"
 pyasn1-modules = ">=0.0.7"
 bcrypt = ">=3.1.7"