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/README.md b/README.md
index cca05cd..52e6503 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,9 @@
 
 ## Documentation
 
-Documentation is generated with `doxygen` tool.
+Documentation is generated with `doxygen` tool. Dependency to `doxygen`
+tool is optional. If not installed, then `doxygen-doc` target will not
+be created to Makefile.
 
 By default `make doxygen-doc` creates HTML, PDF and PS documents (if
 the needed tools are available). The documents are created to:
@@ -33,10 +35,23 @@
 
 ### Dependencies
 
-Currently, the following libraries are required while building:
+Build-time dependencies:
 
-    boost-devel
-    hiredis-devel
+    boost
+    hiredis
+    doxygen (optional)
+
+Commands to install dependent packages in Fedora:
+
+    sudo dnf install boost-devel
+    sudo dnf install hiredis-devel
+    sudo dnf install doxygen
+
+Commands to install dependent packages in Debian/Ubuntu:
+
+    sudo apt install libboost-all-dev
+    sudo apt install libhiredis-dev
+    sudo apt install doxygen
 
 ### Compilation in the source directory
 
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'
+