fix: all pipeline failures (#1221)

* fix: update conditional static assertion
There is a static assertion that spuriously fails on MSVC that was
version checked. Unfortunately it fires every time there is a new
compiler update, so for now we will remove the version check and add it
back once the compiler bug is fixed.

* fix: ios pipeline failure

Looks like somewhere along the line, the iOS simulator changed the range
of support iOS versions. This changes bumps the version from 9 to 12.0.

Also noticed that the GSL OSX bundle version was quite out of date. I
bumped this from 3.1.0 to 4.2.0 and created an upgrade checklist file in
docs/ so we don't forget these types of tasks in the future.

* bump xcode version from 15.4 to 16.4

* fix compiler warning when building gtest for ios

* allow for missing include dirs on command line

* replace windows-2019 with windows-2025

* update visual studio versions after runner bump

* PR feedback: make sure markdown links are syntactically correct

.github/workflows/ios.yml

@@ -25,11 +25,12 @@ jobs:
             -GXcode \
             -DCMAKE_SYSTEM_NAME=iOS \
             "-DCMAKE_OSX_ARCHITECTURES=arm64;x86_64" \
-            -DCMAKE_OSX_DEPLOYMENT_TARGET=9 \
+            -DCMAKE_OSX_DEPLOYMENT_TARGET=12.0 \
             -DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY \
             "-DMACOSX_BUNDLE_GUI_IDENTIFIER=GSL.\$(EXECUTABLE_NAME)" \
-            -DMACOSX_BUNDLE_BUNDLE_VERSION=3.1.0 \
-            -DMACOSX_BUNDLE_SHORT_VERSION_STRING=3.1.0 \
+            -DMACOSX_BUNDLE_BUNDLE_VERSION=4.2.0 \
+            -DMACOSX_BUNDLE_SHORT_VERSION_STRING=4.2.0 \
+            -DCMAKE_CXX_FLAGS="-Wno-missing-include-dirs" \
             ..
 
       - name: Build