Support case insensitive meta attributes?

[keyle]

Some meta attributes can be capitalised, causing to have to duplicate them as below:

        Author1   []string `pagser:"meta[name='author']->attrSplit(content)"`
	Author2   []string `pagser:"meta[name='Author']->attrSplit(content)"`
	Desc1     []string `pagser:"meta[name='description']->attrSplit(content)"`
	Desc2     []string `pagser:"meta[name='Description']->attrSplit(content)"`
	Keywords1 []string `pagser:"meta[name='keywords']->attrSplit(content)"`
	Keywords2 []string `pagser:"meta[name='Keywords']->attrSplit(content)"`

Any suggestion for this?

go 1.21.0 / github.com/foolin/pagser v0.1.5

Thanks!