Add SDK reference to snap version, drop version's patch

[farshidtz]

Summary

• Add SDK reference to snap version; closes Improve snap versioning #72
• Drop version's patch. See below.

The following options have been considered:

Option 1

Don't use semver. In semver, the MINOR should change when the SDK changes. We can't easily automate that.

That gives us:

• latest/stable: 2.0+chip-v1.3.0.0
• latest/edge: 2.0+chip-hash

Option 2

Use semver's pre-release versioning on edge, and stable on releases.

That gives us:

• latest/stable: 2.0.0+chip-1.3.0.0
• latest/edge: 2.1.0-chip-hash (note the bumped MINOR and use of hyphen to indicate pre-release).

Option 2 was discarded as the manual versioning efforts are high and prone to human errors. Moreover, the snap doesn't require that level of details in the versioning.

Related to #74

Testing Steps

$ snapcraft -v
...
Creating snap package...                                                                                                                                 
Created snap package matter-pi-gpio-commander_2.0+chip-f6ac9266_arm64.snap 

[jpm-canonical]

LGTM