bump mono to 5.20

Author: thelamer

Dockerfile

@@ -13,7 +13,7 @@ RUN \
 	apt-transport-https && \
  echo "**** add mono repository ****" && \
  apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF && \
- echo "deb http://download.mono-project.com/repo/ubuntu bionic/snapshots/5.14 main" | tee /etc/apt/sources.list.d/mono-official.list && \
+ echo "deb http://download.mono-project.com/repo/ubuntu bionic/snapshots/5.20 main" | tee /etc/apt/sources.list.d/mono-official.list && \
  echo "**** add mediaarea repository ****" && \
  apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys C5CDF62C7AE05CC847657390C10E11090EC0E438 && \
  echo "deb https://mediaarea.net/repo/deb/ubuntu bionic main" | tee /etc/apt/sources.list.d/mediaarea.list && \

Dockerfile.aarch64

@@ -13,7 +13,7 @@ RUN \
 	apt-transport-https && \
  echo "**** add mono repository ****" && \
  apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF && \
- echo "deb http://download.mono-project.com/repo/ubuntu bionic/snapshots/5.14 main" | tee /etc/apt/sources.list.d/mono-official.list && \
+ echo "deb http://download.mono-project.com/repo/ubuntu bionic/snapshots/5.20 main" | tee /etc/apt/sources.list.d/mono-official.list && \
  echo "**** add mediaarea repository ****" && \
  apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys C5CDF62C7AE05CC847657390C10E11090EC0E438 && \
  echo "deb https://mediaarea.net/repo/deb/ubuntu bionic main" | tee /etc/apt/sources.list.d/mediaarea.list && \

Dockerfile.armhf

@@ -13,7 +13,7 @@ RUN \
 	apt-transport-https && \
  echo "**** add mono repository ****" && \
  apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF && \
- echo "deb http://download.mono-project.com/repo/ubuntu bionic/snapshots/5.14 main" | tee /etc/apt/sources.list.d/mono-official.list && \
+ echo "deb http://download.mono-project.com/repo/ubuntu bionic/snapshots/5.20 main" | tee /etc/apt/sources.list.d/mono-official.list && \
  echo "**** add mediaarea repository ****" && \
  apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys C5CDF62C7AE05CC847657390C10E11090EC0E438 && \
  echo "deb https://mediaarea.net/repo/deb/ubuntu bionic main" | tee /etc/apt/sources.list.d/mediaarea.list && \