Add API key for drone automated builds

.drone.yml

@@ -5,12 +5,15 @@ name: default
 steps:
 - name: Build
   image: golang
+  environment:
+    NASA_TOKEN:
+      from_secret: nasa_api
   commands:
   - go get github.com/reujab/wallpaper
   - go vet -v
-  - GOOS="linux" go build -o SpaceFace-Linux
-  - GOOS="windows" go build -o SpaceFace-Win.exe
-  - GOOS="darwin" go build -o SpaceFace-macOS
+  - GOOS="linux" go build -ldflags="-w -s -x main.api_key=${NASA_TOKEN}" -o SpaceFace-Linux
+  - GOOS="windows" go build -ldflags="-w -s -x main.api_key=${NASA_TOKEN}" -o SpaceFace-Win.exe
+  - GOOS="darwin" go build -ldflags="-w -s -x main.api_key=${NASA_TOKEN}" -o SpaceFace-macOS
 - name: gitea_release
   image: plugins/gitea-release
   settings:

main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"encoding/json"
+	"fmt"
 	"io"
 	"log"
 	"net/http"
@@ -12,10 +13,14 @@ import (
 
 var (
 	apod APODResponse
+	api_key string
 )
 
 func main() {
-	resp, err := http.Get("https://api.nasa.gov/planetary/apod?api_key=DEMO_KEY")
+	if len(api_key) == 0 {
+		api_key="DEMO_KEY"
+	}
+	resp, err := http.Get(fmt.Sprintf("https://api.nasa.gov/planetary/apod?api_key=%+v", api_key))
 	if err != nil {
 		log.Fatalf("\nUnable to get NASA API Response\n")
 		return