Fix length issues

[inari06]

Issues:

/tmp ./spdx-sbom-generator -p ironclad/harbor -o /tmp/bom
INFO[2023-02-21T18:00:14-08:00] Starting to generate SPDX ...
INFO[2023-02-21T18:00:14-08:00] Running generator for Module Manager: `yarn` with output `/tmp/bom/bom-yarn.spdx`
INFO[2023-02-21T18:00:14-08:00] Current Language Version 1.22.19
panic: runtime error: index out of range [1] with length 1

goroutine 1 [running]:
spdx-sbom-generator/internal/modules/yarn.appendNestedDependencies(0xc00352a000, 0x1210, 0x1362, 0x1210, 0x1362, 0x0)
	/github/workspace/internal/modules/yarn/handler.go:372 +0x8ba
spdx-sbom-generator/internal/modules/yarn.(*yarn).ListModulesWithDeps(0xc0000b8190, 0x7ff7bfefebc9, 0xf, 0x0, 0x0, 0x1, 0x1, 0x1920720)
	/github/workspace/internal/modules/yarn/handler.go:154 +0xdf
spdx-sbom-generator/internal/modules.(*Manager).Run(0xc002f62000, 0x4, 0x1955d89)
	/github/workspace/internal/modules/modules.go:94 +0x14d
spdx-sbom-generator/internal/handler.(*spdxHandler).Run(0xc002f64000, 0x7, 0x7ff7bfefebc9)
	/github/workspace/internal/handler/spdx.go:73 +0x2ee
main.generate(0x2255c80, 0xc002f0f180, 0x0, 0x4)
	/github/workspace/cmd/generator/generator.go:105 +0x433
github.com/spf13/cobra.(*Command).execute(0x2255c80, 0xc0000b8010, 0x4, 0x4, 0x2255c80, 0xc0000b8010)
	/go/pkg/mod/github.com/spf13/[email protected]/command.go:856 +0x2aa
github.com/spf13/cobra.(*Command).ExecuteC(0x2255c80, 0x0, 0x0, 0x0)
	/go/pkg/mod/github.com/spf13/[email protected]/command.go:960 +0x349
github.com/spf13/cobra.(*Command).Execute(...)
	/go/pkg/mod/github.com/spf13/[email protected]/command.go:897
main.main()
	/github/workspace/cmd/generator/generator.go:37 +0x5d

panic: runtime error: index out of range [1] with length 1

goroutine 1 [running]:
github.com/spdx/spdx-sbom-generator/pkg/modules/yarn.appendNestedDependencies({0xc003680000, 0x1210, 0x1?})
	/tmp/spdx-sbom-generator/pkg/modules/yarn/handler.go:397 +0x752
github.com/spdx/spdx-sbom-generator/pkg/modules/yarn.(*yarn).ListModulesWithDeps(0xc000022190?, {0x7ff7bfefeba5, 0x14}, {0x16?, 0xc00315f9b0?})
	/tmp/spdx-sbom-generator/pkg/modules/yarn/handler.go:169 +0x85
github.com/spdx/spdx-sbom-generator/pkg/modules.(*Manager).Run(0xc000022230)
	/tmp/spdx-sbom-generator/pkg/modules/modules.go:102 +0x15a
github.com/spdx/spdx-sbom-generator/pkg/handler.(*spdxHandler).Run(0xc0030dc000)
	/tmp/spdx-sbom-generator/pkg/handler/spdx.go:88 +0x309
main.generate(0x1fc8ea0, {0x17e1cc2?, 0x4?, 0x4?})
	/tmp/spdx-sbom-generator/cmd/generator/generator.go:121 +0x373
github.com/spf13/cobra.(*Command).execute(0x1fc8ea0, {0xc000128010, 0x4, 0x4})
	/Users/nari.mulakala/work/gowork/pkg/mod/github.com/spf13/[email protected]/command.go:856 +0x663
github.com/spf13/cobra.(*Command).ExecuteC(0x1fc8ea0)
	/Users/nari.mulakala/work/gowork/pkg/mod/github.com/spf13/[email protected]/command.go:960 +0x39d
github.com/spf13/cobra.(*Command).Execute(...)
	/Users/nari.mulakala/work/gowork/pkg/mod/github.com/spf13/[email protected]/command.go:897
main.main()
	/tmp/spdx-sbom-generator/cmd/generator/generator.go:39 +0x65