Actionlint reproduction of issue 481

Steps

# Install actionlint binary
make tools/actionlint

# Run actionlint
./tools/actionlint

Testing different versions

# Bug is present in
go run github.com/rhysd/actionlint/cmd/actionlint@v1.7.0
go run github.com/rhysd/actionlint/cmd/actionlint@v1.7.1
go run github.com/rhysd/actionlint/cmd/actionlint@v1.7.2
go run github.com/rhysd/actionlint/cmd/actionlint@v1.7.3

# Fixed in
go run github.com/rhysd/actionlint/cmd/actionlint@v1.7.4
go run github.com/rhysd/actionlint/cmd/actionlint@v1.7.5
go run github.com/rhysd/actionlint/cmd/actionlint@v1.7.6
go run github.com/rhysd/actionlint/cmd/actionlint@v1.7.7