GitHub: add auto-labelling to pull requests

.github/labeler.yml

@@ -0,0 +1,38 @@
+lib:
+  - lib/**/*
+  - include/**/*
+
+core:
+  - db/**/*
+  - display/**/*
+  - general/**/*
+  - imagery/**/*
+  - misc/**/*
+  - ps/**/*
+  - raster/**/*
+  - raster3d/**/*
+  - scripts/**/*
+  - temporal/**/*
+  - vector/**/*
+
+GUI:
+  - gui/**/*
+
+Windows:
+  - mswindows/**/*
+
+MacOS:
+  - macosx/**/*
+
+Linux:
+  - rpm/**/*
+  - singularity/**/*
+
+docker:
+  - docker/**/*
+
+docs:
+  - doc/**/*
+
+locale:
+  - locale/**/*

.github/workflows/label.yml

@@ -0,0 +1,19 @@
+# This workflow will triage pull requests and apply a label based on the
+# paths that are modified in the pull request.
+#
+# To use this workflow, you will need to set up a .github/labeler.yml
+# file with configuration.  For more information, see:
+# https://github.com/actions/labeler/blob/master/README.md
+
+name: Labeler
+on: [pull_request]
+
+jobs:
+  label:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/labeler@v2
+      with:
+        repo-token: "${{ secrets.GITHUB_TOKEN }}"