Fix dockerfile.

It was broken because the practicerom package changed stuff and apt didn't like whatever changed.
This is the commit that seems to have broken how the old practicerom package worked: e7bec93b0b (diff-b335630551682c19a781afebcf4d07bf978fb1f8ac04c6bf87428ed5106870f5)

Dockerfile

@@ -3,10 +3,15 @@ FROM ubuntu:24.04 AS build
 ENV TZ=UTC
 ENV LANG=C.UTF-8
 
+RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
+
+# Add source for practicerom-dev install
+RUN apt-get update && apt-get install -y curl && \
+    curl -o /etc/apt/trusted.gpg.d/practicerom.gpg https://practicerom.com/public/packages/practicerom.gpg && \
+    echo 'deb [arch=amd64] http://practicerom.com/public/packages/debian unstable main' > /etc/apt/sources.list.d/practicerom.list
+
 # Install Required Dependencies
-RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone && \
-    apt-get update && apt-get install -y \
-    curl \
+RUN apt-get update && apt-get install -y \
     build-essential \
     binutils-mips-linux-gnu \
     pkg-config \
@@ -20,12 +25,7 @@ RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone &
     vim \
     clang-tidy-14 \
     clang-format-14 \
-    libpng-dev && \
-    # Add source for practicerom-dev install
-    curl https://practicerom.com/public/packages/debian/pgp.pub | apt-key add - && \ 
-    echo deb http://practicerom.com/public/packages/debian staging main >/etc/apt/sources.list.d/practicerom.list && \
-    apt-get update && \
-    apt-get install -y \
+    libpng-dev \
     practicerom-dev && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*