Test infrastructure (#52)

* Adding tests target

* Adding test plan

* Fixing deps

* Add test workflow

* Add config

* More

* Change workflow

* Add test step to release

* Signing changes

* Signing changes

* Remove 11.4 specific test

* More signing

Config/Secretive.xctestplan

@@ -0,0 +1,41 @@
+{
+  "configurations" : [
+    {
+      "id" : "5896AE5A-6D5A-48D3-837B-668B646A3273",
+      "name" : "Configuration 1",
+      "options" : {
+
+      }
+    }
+  ],
+  "defaultOptions" : {
+
+  },
+  "testTargets" : [
+    {
+      "parallelizable" : true,
+      "target" : {
+        "containerPath" : "container:Secretive.xcodeproj",
+        "identifier" : "50617DAF23FCE4AB0099B055",
+        "name" : "SecretKitTests"
+      }
+    },
+    {
+      "parallelizable" : true,
+      "target" : {
+        "containerPath" : "container:Secretive.xcodeproj",
+        "identifier" : "5099A073240242BA0062B6F2",
+        "name" : "SecretAgentKitTests"
+      }
+    },
+    {
+      "parallelizable" : true,
+      "target" : {
+        "containerPath" : "container:Secretive.xcodeproj",
+        "identifier" : "50617D9323FCE48E0099B055",
+        "name" : "SecretiveTests"
+      }
+    }
+  ],
+  "version" : 1
+}