Update application.properties

src/main/resources/application.properties

@@ -2,8 +2,8 @@
 
 spring.security.filter.order=2
 spring.datasource.url=${DB_URL}
-spring.datasource.username=${USERNAME}
-spring.datasource.password=${PASSWORD}
+spring.datasource.username=${{secrets.USERNAME}}
+spring.datasource.password=${{secrets.PASSWORD}}
 spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
 spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL8Dialect
 
@@ -25,7 +25,7 @@ spring.devtools.livereload.enabled=false
 
 spring.mail.host=smtp.gmail.com
 spring.mail.port=587
-spring.mail.username=${EMAIL}
-spring.mail.password=${EMAIL_PASSWORD}
+spring.mail.username=${{secrets.EMAIL}}
+spring.mail.password=${{secrets.EMAIL_PASSWORD}}
 spring.mail.properties.mail.smtp.auth=true
 spring.mail.properties.mail.smtp.starttls.enable=true