feat: Replace paru with yay

Paru has not been updated in months and is incompatible with the current
version of pacman / libalpm, which is v16.0.0. See upstream issue [1].

Replace paru with yay so the action works again.

Also updated CI test with latest Spotify as the old version is gone now.

[1] https://github.com/Morganamilo/paru/issues/1454

Dockerfile

@@ -10,9 +10,9 @@ RUN useradd -m builder && \
 WORKDIR /home/builder
 USER builder
 
-# Install paru
-RUN git clone https://aur.archlinux.org/paru-bin.git
-RUN cd paru-bin && makepkg -si --noconfirm
+# Install yay
+RUN git clone https://aur.archlinux.org/yay-bin.git
+RUN cd yay-bin && makepkg -si --noconfirm
 
 # Copy files
 COPY LICENSE README.md /