fix Fix partial theme property (#25)

Author: Esemesek

typings/__tests__/index.test.tsx

@@ -54,6 +54,6 @@ const ThemedTitle = withTheme(TitleComponent);
 
 const App = () => (
   <ThemeProvider theme={themes.default}>
-    <ThemedTitle title="React Theme Provider" primaryColor="pink" />
+    <ThemedTitle title="React Theme Provider" theme={{ primaryColor: 'pink' }} />
   </ThemeProvider>
 );

typings/index.d.ts

@@ -11,7 +11,7 @@ export type ThemingType<Theme, PartialTheme> = {
   ThemeProvider: ThemeProviderType<Theme>;
   withTheme: <Props extends { theme: Theme }>(
     Comp: React.ComponentType<Props>
-  ) => React.ComponentType<Without<Props, "theme"> & PartialTheme>;
+  ) => React.ComponentType<Without<Props, "theme"> & { theme: PartialTheme }>;
 };
 
 // Library exports