fix: add gd32h759i-start to CI

.github/workflows/bsp_buildings.yml

@@ -248,6 +248,7 @@ jobs:
                 - "gd32/arm/gd32407v-lckfb"
                 - "gd32/arm/gd32450z-eval" 
                 - "gd32/arm/gd32470z-lckfb"
+                - "gd32/arm/gd32h759i-start"
                 - "n32/n32g43xcl-stb"
                 - "n32/n32g45xcl-stb"
                 - "n32/n32g45xml-stb"