Increase version to 0.20.1-1 (patch release)

Use .001 for nuget, because it doesn't allow - for patch releases.

Gettext.Tools.nuspec

@@ -2,7 +2,7 @@
 <package xmlns="http://schemas.microsoft.com/packaging/2011/08/nuspec.xsd">
     <metadata>
         <id>Gettext.Tools</id>
-        <version>0.20.1</version>
+        <version>0.20.1.001</version>
         <title>GNU gettext tools for Windows</title>
         <authors>Vaclav Slavik</authors>
         <license type="expression">GPL-3.0-or-later</license>

Makefile

@@ -3,7 +3,9 @@ GETTEXT_VERSION   = 0.20.1
 LIBICONV_VERSION  = 1.16
 
 # version of the gettext-tools-windows package; usually same as GETTEXT_VERSION
-PACKAGE_VERSION   = $(GETTEXT_VERSION)
+# use "-n" suffix; for NuGet, use ".00n" suffix instead, e.g. 0.20.1-1 and 0.20.1.001
+PACKAGE_VERSION   = $(GETTEXT_VERSION)-1
+NUGET_VERSION     = $(GETTEXT_VERSION).001
 
 _space := $(subst ,, )
 GETTEXT_VERSION_SHORT := $(subst $(_space),.,$(wordlist 1,2,$(subst ., ,$(GETTEXT_VERSION))))
@@ -45,7 +47,7 @@ USR_LOCAL   = $(STAGEDIR)/usr/local
 DISTDIR     = $(BUILDDIR)/dist
 
 ARCHIVE_FILE = $(BUILDDIR)/gettext-tools-windows-$(PACKAGE_VERSION).zip
-NUGET_FILE   = $(BUILDDIR)/Gettext.Tools.$(PACKAGE_VERSION).nupkg
+NUGET_FILE   = $(BUILDDIR)/Gettext.Tools.$(NUGET_VERSION).nupkg
 
 LIBICONV_FILE := libiconv-$(LIBICONV_VERSION).tar.gz
 LIBICONV_URL  := http://ftp.gnu.org/pub/gnu/libiconv/$(LIBICONV_FILE)