Add PackageCloud.io release file

Version 1.0.4-1 will be released for RIC Amber release.

Packages, which will be now released, were pushed to staging area
by this Jenkins job execution:

https://jenkins.o-ran-sc.org/job/ric-plt-sdl-docker-ci-pc-merge-master/5/

Package releasing instructions for reference:

https://docs.releng.linuxfoundation.org/projects/global-jjb/en/latest/jjb/lf-release-jobs.html#packagecloud-release-files

Additionally, improved README.md file instructions based on received
feedback.

Signed-off-by: Rolf Badorek <rolf.badorek@nokia.com>
Change-Id: Ibc3cda11d127e877b5a97c83c377139e91f2a013
diff --git a/releases/packagecloud-release-sdl.yaml b/releases/packagecloud-release-sdl.yaml
new file mode 100644
index 0000000..27a1ac5
--- /dev/null
+++ b/releases/packagecloud-release-sdl.yaml
@@ -0,0 +1,8 @@
+---
+distribution_type: packagecloud
+package_name:
+    - name: 'sdl_1.0.4-1_amd64.deb'
+    - name: 'sdl-dev_1.0.4-1_amd64.deb'
+    - name: 'sdl-1.0.4-1.x86_64.rpm'
+    - name: 'sdl-devel-1.0.4-1.x86_64.rpm'
+