[py] Pin key dependencies in the build

Author: AutomatedTester

py/BUILD.bazel

@@ -98,9 +98,9 @@ py_wheel(
     python_tag = "py3",
     python_requires = "~=3.7",
     requires = [
-        "urllib3[secure]",
-        "trio",
-        "trio-websocket",
+        "urllib3[secure]==1.26.2",
+        "trio==0.17.0",
+        "trio-websocket==0.9.0",
     ],
     strip_path_prefixes = [
         "py",

py/requirements.txt

@@ -12,13 +12,13 @@ multidict
 outcome
 pluggy
 py
-pytest
-pytest-instafail
-pytest-mock
-pytest-trio
+pytest==6.1.2
+pytest-instafail==0.4.2
+pytest-mock==3.3.1
+pytest-trio==0.7.0
 sortedcontainers
 sniffio
-trio
-trio_websocket
-urllib3
+trio==0.17.0
+trio_websocket==0.9.0
+urllib3==1.26.2
 zipp