fix: environment handling windows (host mode) (#1732)

* fix: environment handling windows (host mode)

* fixup

* fixup

* add more tests

* fixup

* fix setenv

* fixes

* [skip ci] Apply suggestions from code review

Co-authored-by: Jason Song <i@wolfogre.com>

* Update side effects

---------

Co-authored-by: Jason Song <i@wolfogre.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

pkg/runner/step_test.go

@@ -63,7 +63,9 @@ func TestMergeIntoMap(t *testing.T) {
 
 	for _, tt := range table {
 		t.Run(tt.name, func(t *testing.T) {
-			mergeIntoMap(&tt.target, tt.maps...)
+			mergeIntoMapCaseSensitive(tt.target, tt.maps...)
+			assert.Equal(t, tt.expected, tt.target)
+			mergeIntoMapCaseInsensitive(tt.target, tt.maps...)
 			assert.Equal(t, tt.expected, tt.target)
 		})
 	}