feat(weather): interfaces

src/main/java/eirb/pg203/Temperature.java

@@ -0,0 +1,5 @@
+package eirb.pg203;
+
+public class Temperature {
+
+}

src/main/java/eirb/pg203/WeatherDataAPI.java

@@ -0,0 +1,5 @@
+package eirb.pg203;
+
+public interface WeatherDataAPI {
+    Temperature getTemperature(int day, String city);
+}

src/main/java/eirb/pg203/WeatherDisplay.java

@@ -0,0 +1,7 @@
+package eirb.pg203;
+
+public interface WeatherDisplay {
+    void display();
+    
+    void addAPI(WeatherDataAPI w);
+}