Update issue templates

Author: ivan-hc

.github/ISSUE_TEMPLATE/add-application.md

@@ -0,0 +1,12 @@
+---
+name: Add application
+about: Add a portable app or AppImage not in this catalog
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+Before opening any issue, we assume you have read our CONTRIBUTING page
+
+https://github.com/Portable-Linux-Apps/Portable-Linux-Apps.github.io/blob/main/CONTRIBUTING.md

.github/ISSUE_TEMPLATE/add-update-icon.md

@@ -0,0 +1,12 @@
+---
+name: Add/update icon
+about: Add a missing icon or replace an existing one
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+Before opening any issue, we assume you have read our CONTRIBUTING page
+
+https://github.com/Portable-Linux-Apps/Portable-Linux-Apps.github.io/blob/main/CONTRIBUTING.md

.github/ISSUE_TEMPLATE/add-update-info-about-a-program.md

@@ -0,0 +1,12 @@
+---
+name: Add/update info about a program
+about: Update info about a program listed in this catalog
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+Before opening any issue, we assume you have read our CONTRIBUTING page
+
+https://github.com/Portable-Linux-Apps/Portable-Linux-Apps.github.io/blob/main/CONTRIBUTING.md