Use libssl-dev on Ubuntu

[brylie]

Fixes #2812

Use libssl-dev instead of hard-coding the version of libssl for every Ubuntu release. libssl-dev is available in Ubuntu going back to 16.04:
https://packages.ubuntu.com/search?keywords=libssl-dev

[msftclas]

All CLA requirements met.

[brylie]

Ping @IlyaBiryukov @Priya91 @Chuxel @BrunoGuardia

[IlyaBiryukov]

It's kind of awkward for an application to take a dependency over a developer api lib. I think we should hard code the version of libssl for every supported Ubuntu release. And, of course, document explicitly what releases are supported.

[brylie]

From what I can tell, the libssl-dev seems to be a metapackage for the latest stable version of the package as well as suggesting installing docs.

This issue stems from the installation script not being kept up-to-date with supported Ubuntu releases and newer libssl releases. How will the installation script/documentation be kept up-to-date to reflect supported libssl releases and Ubuntu versions?

[brylie]

Another alternative on Ubuntu would be to use the openssl package.

The idea being to avoid the script going out of date by relying on a stable Ubuntu package name or metapackage.

[IlyaBiryukov]

There is a bunch of /usr/include/openssl/*.h files in the list of files or libssl-dev.

Dotnet core dependencies have libssl, and say nothing about openssl, up until it gets supported in 3.0, as declared in Whats new in .NET Core 3.0.
We don't have plans to migrate to dotnet core 3.0 yet.

So the only option is to use libssl.

[IlyaBiryukov]

Actually, I see that dotnet core guys back ported openssl 1.0 and 1.1. support to dotnet 2.1 with this PR.
So using openssl may be an option then.

[IlyaBiryukov]

cc @jasongin

[brylie]

I changed the script to use openssl.

[IlyaBiryukov]

We're going to test the updated script a little bit, and then it'll be good to go.