Add mkdir of the SOURCE_DIR before setting WORKDIR

deployment/Dockerfile.docker.amd64

@@ -4,6 +4,8 @@ ARG ARTIFACT_DIR=/jellyfin
 
 FROM mcr.microsoft.com/dotnet/core/sdk:${DOTNET_VERSION}-buster as builder
 
+RUN mkdir ${SOURCE_DIR}
+
 WORKDIR ${SOURCE_DIR}
 COPY . .
 

deployment/Dockerfile.docker.arm64

@@ -4,6 +4,8 @@ ARG ARTIFACT_DIR=/jellyfin
 
 FROM mcr.microsoft.com/dotnet/core/sdk:${DOTNET_VERSION}-buster as builder
 
+RUN mkdir ${SOURCE_DIR}
+
 WORKDIR ${SOURCE_DIR}
 COPY . .
 

deployment/Dockerfile.docker.armhf

@@ -4,6 +4,8 @@ ARG ARTIFACT_DIR=/jellyfin
 
 FROM mcr.microsoft.com/dotnet/core/sdk:${DOTNET_VERSION}-buster as builder
 
+RUN mkdir ${SOURCE_DIR}
+
 WORKDIR ${SOURCE_DIR}
 COPY . .