Remove obsolete Group tag

References: https://fedoraproject.org/wiki/Changes/Remove_Group_Tag

mingw-libtiff.spec

@@ -5,7 +5,6 @@ Name:           mingw-libtiff
 Version:        4.0.9
 Release:        2%{?dist}
 License:        libtiff
-Group:          System Environment/Libraries
 URL:            http://www.simplesystems.org/libtiff/
 Source:         ftp://ftp.simplesystems.org/pub/libtiff/tiff-%{version}.tar.gz
 
@@ -52,7 +51,6 @@ format image files.
 %package -n mingw32-libtiff-static
 Summary:        Static version of the MinGW Windows LibTIFF library
 Requires:       mingw32-libtiff = %{version}-%{release}
-Group:          Development/Libraries
 
 %description -n mingw32-libtiff-static
 Static version of the MinGW Windows LibTIFF library.
@@ -73,7 +71,6 @@ format image files.
 %package -n mingw64-libtiff-static
 Summary:        Static version of the MinGW Windows LibTIFF library
 Requires:       mingw64-libtiff = %{version}-%{release}
-Group:          Development/Libraries
 
 %description -n mingw64-libtiff-static
 Static version of the MinGW Windows LibTIFF library.