Added AMBR Extended bitrates for 5g and Makefile for testing (#156)

Signed-off-by: Oriol Batalla <obatalla@fb.com>

Fix sm client build. (#155)

Signed-off-by: Evgeniy Makeev <evgeniym@fb.com>

Merge pull request #142 from emakeev/s6a_protocol_fix

S6a protocol fix

Add /v4 to import path

From now on, users must import from /v4 onwards when using modules.

Release v4.0.0 with go.mod and go.sum

Opting for not creating a subdirectory for version, similar to what was
done in golang.org/x/{net,tools} etc.

These files were created by setting GO111MODULE=on and executing
"go mod init" and "go mod tidy".

There are several extraneous dependencies in go-diameter as of today,
mostly because of examples/s6a_proxy depending on protobuf. In the
future we might consider moving this example out to its own repo to
reduce dependencies.

fix test case build error

Fix for the Time type based on RFC 868

Merge pull request #11 from fiorix/v3

V3

Bug fix for data length

Rename CMD to Command