Updates to dependencies and GitHub workflows

[gaby]

• Bump all dependencies
• Add dependabot to track go and github-action dependencies automatically
• Update the github-workflow to test gotestsum against the latest Golang version and multiple platforms

Note: The following tests are failing:

=== RUN   TestE2E_RerunFails/first_run_has_errors,_abort_rerun
    main_e2e_test.go:69: assertion failed: 
        --- expected
        +++ actual
        @@ -1,6 +1,11 @@
        +FAIL testjson/internal/broken
        +
        +=== Failed
        +=== FAIL: testjson/internal/broken 
        +FAIL	gotest.tools/gotestsum/testjson/internal/broken [build failed]
         
         === Errors
         ../testjson/internal/broken/broken.go:5:21: undefined: somepackage
         
        -DONE 0 tests, 1 error
        +DONE 0 tests, 1 failure, 1 error
         
        
        
        You can run 'go test . -update' to automatically update testdata/e2e/expected/TestE2E_RerunFails/first_run_has_errors,_abort_rerun to the new expected value.'
        
--- FAIL: TestE2E_RerunFails/first_run_has_errors,_abort_rerun (0.06s)
FAIL cmd.TestE2E_RerunFails/first_run_has_errors,_abort_rerun (0.06s)
=== RUN   TestE2E_RerunFails
--- FAIL: TestE2E_RerunFails (1.66s)
FAIL cmd.TestE2E_RerunFails (1.66s)

FAIL cmd

=== Skipped
=== SKIP: testjson TestNewDotFormatter (0.00s)
WARN Failed to detect terminal width for dots format, error: inappropriate ioctl for device
    dotformat_test.go:135: !ok: no terminal width

=== SKIP: testjson TestGetPkgPathPrefix/with_go_path (0.00s)
    pkgpathprefix_test.go:22: isGoModuleEnabled()

=== Failed
=== FAIL: cmd TestE2E_RerunFails/first_run_has_errors,_abort_rerun (0.06s)
    main_e2e_test.go:69: assertion failed: 
        --- expected
        +++ actual
        @@ -1,6 +1,11 @@
        +FAIL testjson/internal/broken
        +
        +=== Failed
        +=== FAIL: testjson/internal/broken 
        +FAIL	gotest.tools/gotestsum/testjson/internal/broken [build failed]
         
         === Errors
         ../testjson/internal/broken/broken.go:5:21: undefined: somepackage
         
        -DONE 0 tests, 1 error
        +DONE 0 tests, 1 failure, 1 error
         
        
        
        You can run 'go test . -update' to automatically update testdata/e2e/expected/TestE2E_RerunFails/first_run_has_errors,_abort_rerun to the new expected value.'
        
=== FAIL: cmd TestE2E_RerunFails (1.66s)