Update pymsalruntime minimum version to 0.20.6 (#919)

Bump the minimum required version of pymsalruntime from
0.14/0.17/0.18 to 0.20.6 across all supported platforms
(Windows, macOS, Linux).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: fengga

setup.cfg

@@ -63,11 +63,11 @@ broker =
     # most existing MSAL Python apps do not have the redirect_uri needed by broker.
     #
     # We need pymsalruntime.CallbackData introduced in PyMsalRuntime 0.14
-    pymsalruntime>=0.14,<0.21; python_version>='3.8' and platform_system=='Windows'
+    pymsalruntime>=0.20.6,<0.21; python_version>='3.8' and platform_system=='Windows'
     # On Mac, PyMsalRuntime 0.17+ is expected to support SSH cert and ROPC
-    pymsalruntime>=0.17,<0.21; python_version>='3.8' and platform_system=='Darwin'
+    pymsalruntime>=0.20.6,<0.21; python_version>='3.8' and platform_system=='Darwin'
     # PyMsalRuntime 0.18+ is expected to support broker on Linux
-    pymsalruntime>=0.18,<0.21; python_version>='3.8' and platform_system=='Linux'
+    pymsalruntime>=0.20.6,<0.21; python_version>='3.8' and platform_system=='Linux'
 
 [options.packages.find]
 exclude =