Add ability to search by sha256

lib/artifactory/resources/artifact.rb

@@ -169,6 +169,8 @@ def property_search(options = {})
       #   the MD5 checksum of the artifact to search for
       # @option options [String] :sha1
       #   the SHA1 checksum of the artifact to search for
+      # @option options [String] :sha256
+      #   the SHA256 checksum of the artifact to search for
       # @option options [String, Array<String>] :repos
       #   the list of repos to search
       #
@@ -177,7 +179,7 @@ def property_search(options = {})
       #
       def checksum_search(options = {})
         client = extract_client!(options)
-        params = Util.slice(options, :md5, :sha1, :repos)
+        params = Util.slice(options, :md5, :sha1, :sha256, :repos)
         format_repos!(params)
 
         client.get("/api/search/checksum", params)["results"].map do |artifact|

spec/unit/resources/artifact_spec.rb

@@ -232,12 +232,14 @@ module Artifactory
 
       it "slices the correct parameters" do
         expect(client).to receive(:get).with("/api/search/checksum",
-          md5:  "MD5123",
-          sha1: "SHA456").once
+          md5:    "MD5123",
+          sha1:   "SHA456",
+          sha256: "SHA789").once
         described_class.checksum_search(
-          md5:  "MD5123",
-          sha1: "SHA456",
-          fizz: "foo"
+          md5:    "MD5123",
+          sha1:   "SHA456",
+          sha256: "SHA789",
+          fizz:   "foo"
         )
       end