Drhuffman12/upgrade to crystal 1.1.1 (and 1.2.0-dev) (#1) and expand CouchDB version checks

[drhuffman12]

-[x] Add dependency of crystal-lang/json_mapping.cr/ (JSON.mapping was deprecated and moved to shard.)

• Drop deprecated JSON.mapping crystal-lang/crystal#9527
• https://github.com/crystal-lang/json_mapping.cr

-[x] Add more environment variables for database connection settings with defaults.

• For now, just for tests:

    un = ENV.keys.includes?("TEST_DB_UN") ? ENV["TEST_DB_UN"] : "admin"
    pw = ENV.keys.includes?("TEST_DB_PW") ? ENV["TEST_DB_PW"] : "password"
    ip = ENV.keys.includes?("TEST_DB_IP") ? ENV["TEST_DB_IP"] : "localhost"
    port = ENV.keys.includes?("TEST_DB_PORT") ? ENV["TEST_DB_PORT"] : "5984"
    couchdb_url = ENV.keys.includes?("TEST_DB") ? ENV["TEST_DB"] : "http://#{un}:#{pw}@#{ip}:#{port}"
  

-[x] DEPRECATION: Use ServerInfo#version instead of Vendor#version.
As of v3.x (or earlier?), a call to the server's root (e.g.: GET http://127.0.0.1:5984/)
no longer returns version inside vendor.
In v3.x, response will instead look like (as of v3.1.1):

{
  "couchdb":"Welcome",
  "version":"3.X.X",
  "git_sha":"GIT_SHA_GOES_HERE",
  "uuid":"SOME_UUID_GOES_HERE",
  "features":["access-ready","partitioned","pluggable-storage-engines","reshard","scheduler"],
  "vendor":{"name":"The Apache Software Foundation"}
}

-[x] Allow 3.x.x versions of CouchDB.

• Add is_v2? and is_v3? methods to CouchDB::Response::ServerInfo.
• Tested locally w/ 3.x.x and via CircleCI w/ 2.x.x

-[x] Remove hard-coded crystal key/version from shard.yml (for now).

• Tested (and passed)
  • locally w/ Crystal 1.1.1 [6d9a1d583] (2021-07-26)
  • via CircleCI w/ Crystal 1.2.0-dev [cadc4b3c7] (2021-09-02)

-[x] Bump version of this shard to 0.4.0

• Set CouchDB::VERSION based on shard version value in from shard.yml (to avoid out-of-sync issues).

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drhuffman12/ci_matrix CouchDB (2.x? and 3.x?) (#2) adds CI test runs for matrix CouchDB (2.x? and 3.x?):

• Expand the CI to run the tests against a 'matrix' of version combo's made up of the:
  • latest 2 versions of CouchDB (2.x? and 3.x?)

[drhuffman12]

Hi @vectorselector / @TechMagister, Thanks for all the groundwork on this shard! Please review these changes.

I got the tests to pass for use with:

• Crystal 1.1.1 (local) and 1.2.0-dev (CircleCI)
• CouchDB 2.x.x (CircleCI) / CouchDB 3.x.x (local)

I'm kinda new to CouchDB. I looked at it years ago and am finally circling back to it. So, Next I'll be reading/reviewing CouchDB tutorials and testing/making an example Crystal-based app with CouchDB.