That is my spec file:
Name:       BonsoleRTA-GUI-client
Version:    0.0.1
Release:    0.0.1
Summary:    BonsoleRTA-GUI-client is a GUI client for Rich Text Applications
License:      GPLv3+
BuildRequires: cmake webkit2gtk3-devel gtk3-devel dbus-1-devel
Requires: webkit2gtk3 webkit2gtk3 libgtk-3-0 dbus-1 

BonsoleRTA-GUI-client is a WebKit-Gtk+ client for Rich Text applications, which aims to provide as many ussage possiblities as possible. In opposite to Libgreattao, BonsoleRTA give programmers power to create UI by using special xml application and xslt documents.

%setup -q

mkdir build
cd build
cmake ../../CMakeList.txt
make BonsoleClient


mkdir -p %{buildroot}/%{_bindir}

install -m 0644 build/Bonsole %{buildroot}/%{_bindir}

%dir %{_bindir}

# let's skip this for now
I try command:
osc build openSUSE_Tumbleweed x86_64 ./rpm-spec/BonsoleRTAClient.spec
And receive:
[   14s] -----------------------------------------------------------------
[   14s] I have the following modifications for BonsoleRTAClient.spec:
[   14s] 7c7
[   14s] < Requires: webkit2gtk3 webkit2gtk3 libgtk-3-0 dbus-1 
[   14s] ---
[   14s] > Requires: webkit2gtk3 libgtk-3-0 dbus-1
[   14s] -----------------------------------------------------------------
[   14s] ----- building BonsoleRTAClient.spec (user abuild)
[   14s] -----------------------------------------------------------------
[   14s] -----------------------------------------------------------------
[   14s] + exec rpmbuild -ba --define '_srcdefattr (-,root,root)' --nosignature /home/abuild/rpmbuild/SOURCES/BonsoleRTAClient.spec
[   14s] error: Bad source: /home/abuild/rpmbuild/SOURCES/Bonsole-0.0.1.tar.gz: No such file or directory
[   14s] 
[   14s] localhost.localdomain failed "build BonsoleRTAClient.spec" at Sat Apr 17 10:47:32 UTC 2021.
[   14s]