chore(macOS): Added default values to build settings in template file.

Signed-off-by: Iva Horn <[email protected]>

Author: i2h3

shell_integration/MacOSX/NextcloudIntegration/NextcloudDev/Build.xcconfig.template

@@ -5,14 +5,14 @@
 // The common name of the signing certificate to use for code signing.
 // It must be present in your keychain and a development certificate.
 //
-CODE_SIGN_IDENTITY=Apple Development
+CODE_SIGN_IDENTITY=$(CODE_SIGN_IDENTITY:default=Apple Development)
 
 //
 // Xcode should automatically manage signing assets.
 //
-CODE_SIGN_STYLE = Automatic
+CODE_SIGN_STYLE = $(CODE_SIGN_STYLE:default=Automatic)
 
 //
 // The development team identifier registered with Apple.
 //
-DEVELOPMENT_TEAM=NKUJUXUJ3B
+DEVELOPMENT_TEAM=$(DEVELOPMENT_TEAM:default=NKUJUXUJ3B)