refactor: remove anchor from header templates

[hutson]

Closes #186.

BREAKING CHANGE:

Anchor tags are removed from the changelog header templates. The
rendered Markdown will no longer contain anchor tags proceeding the
version number header that constitutes the changelog header. This means
that consumers of rendered markdown will not be able to use a URL that
has been constructed to contain a version number anchor tag reference,
since the anchor tag won't exist in the rendered markdown.

It's stronly recomended consumers use the full URL path to the release
page for a given version, as that URL is a permalink to that verison,
contains all relavent release information, and does not, otherwise, rely
on the anchor tag being excessible from the current page view.

As an example, for version 2.0.0 of a GitHub project, the following
URL should be used:

• https://github.com/conventional-changelog/releaser-tools/releases/tag/v2.0.0

[hutson]

CC @TheDancingCode @pvdlg

[pvdlg]

Makes sense to me. Using the full URL to the releases (with releases/tags/<tag-name>) works for me.

[hutson]

Successfully published:

conventional-changelog-angular@4.0.0
conventional-changelog-atom@1.0.0
conventional-changelog-cli@2.0.0
conventional-changelog-codemirror@1.0.0
conventional-changelog-core@3.0.0
conventional-changelog-ember@1.0.0
conventional-changelog-eslint@2.0.0
conventional-changelog-express@1.0.0
conventional-changelog-jquery@2.0.0
conventional-changelog-jshint@1.0.0
conventional-changelog-preset-loader@2.0.0
conventional-changelog-writer@4.0.0
conventional-changelog@2.0.0
conventional-commits-filter@2.0.0
conventional-commits-parser@3.0.0
conventional-recommended-bump@3.0.0
git-raw-commits@2.0.0
git-semver-tags@2.0.0
gulp-conventional-changelog@2.0.0
standard-changelog@2.0.0