ci: Remove Travis-CI (#5099)

As explained in #4313, OSGeo ends its Travis subscription. Travis is not a crucial component of our CI, so we are removing it.

Additionally, travis became problematic after the Markdown documentation build was enabled because Travis limits size of the log and terminates the build if it hits the limit.

Author: wenzeslaus

.dockerignore

@@ -3,8 +3,6 @@ docker
 !docker/alpine/grass_tests.sh
 .gitignore
 .github
-.travis
-.travis.yml
 # Do not copy files from previous compilations
 dist.*
 

.github/labeler.yml

@@ -84,9 +84,7 @@ CI:
   - changed-files:
       - any-glob-to-any-file:
           - .github/**
-          - .travis/**
           - binder/**
-          - .travis.yml
           - renovate.json
           - .pre-commit-config.yaml
 Windows:

.travis.yml

@@ -1,6 +1,5 @@
 # GRASS GIS Repository
 
-[![Build Status](https://api.travis-ci.com/OSGeo/grass.svg?branch=main)](https://travis-ci.com/OSGeo/grass)
 [![GCC C/C++ standards check](https://github.com/OSGeo/grass/workflows/GCC%20C/C++%20standards%20check/badge.svg)](https://github.com/OSGeo/grass/actions?query=workflow%3A%22GCC+C%2FC%2B%2B+standards+check%22)
 [![Python code quality check](https://github.com/OSGeo/grass/workflows/Python%20code%20quality%20check/badge.svg)](https://github.com/OSGeo/grass/actions?query=workflow%3A%22Python+code+quality+check%22)
 [![General linting](https://github.com/OSGeo/grass/workflows/General%20linting/badge.svg)](https://github.com/OSGeo/grass/actions?query=workflow%3A%22General+linting%22)

.travis/linux.before_install.sh

@@ -228,8 +228,7 @@ Maintainer: Vaclav Petras
 - Details: <https://github.com/OSGeo/grass/pull/525>
 - CI workflow with:
   - A build job which is not parallelized and is meant for clear & relatively fast
-    check of compilation and building in general. (Duplicating what is running
-    on Travis)
+    check of compilation and building in general.
   - A test job which of course needs to build, but the main focus is to run tests,
     so the compilation is parallelized (depending on nproc) and thus potentially
     less readable. This runs the whole test suite. (You need to run it locally to

.travis/linux.install.sh

@@ -672,8 +672,8 @@ For C/C++ code we additionally use the third party solution `Coverity Scan`_
 where GRASS GIS is registered as project number `1038`_. Also you can use
 `Cppcheck`_ which will show a lot of errors which compilers do not check.
 In any case, set your compiler to high error and warning levels,
-check them and fix them in your code. Furthermore, `Travis-CI`_ is used
-to check if the source code can still be compiled after submitting changes
+check them and fix them in your code. Furthermore, continuous integrations is
+used to check if the source code can still be compiled after submitting changes
 to the repository.
 
 For Python, we recommend pylint and then for style issues pep8 tool
@@ -718,7 +718,6 @@ Further reading
 .. _unittest: https://docs.python.org/2/library/unittest.html
 .. _doctest: https://docs.python.org/2/library/doctest.html
 .. _Coverity Scan: https://scan.coverity.com/
-.. _Travis-CI: https://travis-ci.org/github/OSGeo/grass
 .. _1038: https://scan.coverity.com/projects/1038
 .. _Cppcheck: http://cppcheck.sourceforge.net/
 .. _sandbox: https://svn.osgeo.org/grass/sandbox/wenzeslaus/grass_py_static_check.py