build/windows, devel-docs: The minimum Windows version is actually 10.0.18362.0

DWMWA_USE_IMMERSIVE_DARK_MODE and activeCodePage were introduced on "1903"
The Store version manifest was already using this as minimum version since
day 1, so the commit just extends that minimum version to the Installer.

While is unlikely that users will be affected, we can revert this commit if:
1) LTSC/LTSB users report on tracker that is not possible to install GIMP;
2) we confirm that GIMP works on this machine even with that incompatible API.

build/windows/installer/base_gimp3264.iss

@@ -198,7 +198,8 @@ OutputDir={#GIMP_DIR}
 OutputBaseFileName=gimp-{#CUSTOM_GIMP_VERSION}-setup
 OutputManifestFile=inno.log
 ArchitecturesInstallIn64BitMode=x64os arm64
-MinVersion=10.0
+MinVersion=10.0.18362
+//keep this MinVersion consistent with build\windows\store\AppxManifest.xml and devel-docs\os-support.txt
 
 
 ;3.4.1 INSTALLER PAGES

build/windows/installer/lang/setup.isl.xml.in

@@ -9,9 +9,6 @@
     <config name="AboutSetupNote">
       <value>Setup built by Jernej Simonèiè, jernej-gimp@ena.si</value>
     </config>
-    <config name="WinVersionTooLowError">
-      <value>This version of GIMP requires Windows 10, or a newer version of Windows.</value>
-    </config>
   </section>
 
   <section name="CustomMessages">

build/windows/store/AppxManifest.xml

@@ -18,6 +18,7 @@
     <Logo>Assets\StoreLogo.png</Logo>
   </Properties>
   <Dependencies>
+    <!--keep MinVersion consistent with build\windows\installer\*gimp3264.iss and devel-docs\os-support.txt-->
     <TargetDeviceFamily Name="Windows.Desktop" MinVersion="10.0.18362.0" MaxVersionTested="10.0.26100.0" />
   </Dependencies>
   <Resources>

devel-docs/os-support.txt

@@ -25,7 +25,12 @@ Hardware:
 
 ### Windows
 
-Windows 10 and over.
+Windows 10.0.18362.0 (aka 1903) and over.
+
+(NOTE TO MAINTAINERS:
+If you update this file, so update MinVersion
+on build/windows/installer/*gimp3264.iss and
+on build/windows/store/AppxManifest.xml too)
 
 Hardware:
 * x86 32 and 64-bit