refer to OpenSuSE leap for libhinawa RPM package

It is typical that package repository includes metadata for own packaging,
thus it is reasonable to drop rpm file from the upstream repository.

This commit refers to OpenSUSE Factory for the guide to rpm package.

Signed-off-by: Takashi Sakamoto <[email protected]>

README.rst

@@ -2,7 +2,7 @@
 The libhinawa project
 =====================
 
-2023/07/16
+2023/08/12
 Takashi Sakamoto
 
 Instruction
@@ -152,35 +152,7 @@ How to make DEB package
 How to make RPM package
 =======================
 
-1. Satisfy build dependencies
-
-::
-
-    $ dns install meson glib2-devel gobject-introspection-devel gi-docgen
-
-2. make archive
-
-::
-
-    $ meson setup build
-    $ cd build
-    $ meson dist
-    ...
-    Distribution package /.../libhinawa/build/meson-dist/libhinawa-2.6.0.tar.xz tested
-    Created /.../libhinawa/build/meson-dist/libhinawa-2.6.0.tar.xz
-    $ cd ..
-
-3. copy the archive
-
-::
-
-    $ cp build/meson-dist/libhinawa-2.6.0.tar.xz ~/rpmbuild/SOURCES/
-
-4. build package
-
-::
-
-    $ rpmbuild -bb libhinawa.spec
+- Please refer to `<https://build.opensuse.org/package/show/openSUSE:Factory/libhinawa>`_.
 
 Loss of backward compatibility with version 1 and version 2 releases
 ====================================================================