Refresh "cpanfile" from Makefile.PL, to allow use on Windows.

It had been requesting IO::Pty on Windows, which fails.  Among other
changes, this demotes module "Readonly" from "requires" to "recommends";
to compensate, it changes the GitHub Actions cpanm invocations to
install "recommends" and "suggests".

Author: nmisch

.github/workflows/linux.yml

@@ -36,7 +36,7 @@ jobs:
         uses: perl-actions/[email protected]
         with:
           cpanfile: "cpanfile"
-          args: "--configure-timeout=600"
+          args: "--configure-timeout=600 --with-recommends --with-suggests"
           sudo: false
       - run: perl Makefile.PL
       - run: make test

.github/workflows/macos.yml

@@ -29,7 +29,8 @@ jobs:
         uses: perl-actions/[email protected]
         with:
           cpanfile: "cpanfile"
-          args: "--configure-timeout=600"  # IO-Tty-1.16 exceeded 60s default
+          # IO-Tty-1.16 exceeded 60s default
+          args: "--configure-timeout=600 --with-recommends --with-suggests"
           sudo: false
       - name: Makefile.PL
         run: perl Makefile.PL

cpanfile

@@ -1,7 +1,22 @@
-requires 'IO::Pty'  => 0;
-requires 'Readonly' => 0;
+# The cpanfile specification does not explicitly allow testing $^O or $].  cpanm
+# tolerates this, but other cpanfile consumers might not.
+if ( $^O ne 'MSWin32' ) {
+    requires 'IO::Pty', '1.08';    # not entirely required; see Makefile.PL
+}
+else {
+    requires 'Win32',          '0.27';
+    requires 'Win32::Process', '0.14';
+    requires 'Win32::ShellQuote';
+    requires 'Win32API::File', '0.0901';
+    if ( $] >= 5.021006 ) {
+        requires 'Win32API::File', '0.1203';
+    }
+}
+on 'test' => sub {
+    requires 'Test::More', '0.47';
+    recommends 'Readonly';
+};
 on 'develop' => sub {
-    requires 'Readonly';
     requires 'Test::Pod::Coverage';
     requires 'Pod::Simple';
     requires 'Test::Pod';