Add support for Amazon Linux 2023, bump version to 1.1.0-rc1

* Add support for packaging for Amazon Linux 2023

* Bump version to 1.1.0-rc1

* Tidy up the Makefile a bit

docker/Dockerfile-amazonlinux

@@ -0,0 +1,21 @@
+# Dockerfile.rpm
+
+ARG DISTRO=amazonlinux
+ARG RELEASE=2023
+
+FROM ${DISTRO}:${RELEASE}
+
+ARG DISTRO
+ARG RELEASE
+
+RUN dnf install -y \
+    rpm-build \
+    make \
+    && dnf clean all
+
+RUN echo -e "#!/bin/bash\nmake actually-package-${DISTRO}-${RELEASE}" > /init.sh \
+    && chmod 755 /init.sh
+
+WORKDIR /src
+
+CMD ["/bin/bash", "/init.sh"]