fix: add support for ionicons 5.0.0

[shaneparsons]

PR Type

What kind of change does this PR introduce?
Support for ionicons 5.0.0

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Demos changes
[ ] Other... Please describe:

What is the current behavior?

The names of some ionicons changed as of 5.0.0, breaking arrows in the calendar.
Issue Number: #283

What is the new behavior?

The deprecated names have been replaced with their new variants, fixing the broken icons.

Does this PR introduce a breaking change?

[x] Yes
[ ] No

I don't believe the arrows will show correctly for anybody still using ionicons 4.x.x.

Other information

I tried going through your contributing guidelines before submitting this, but I didn't understand the whole dev folder concept and kept getting compiler errors... In frustration, I simply made the bare minimum changes needed, which is what you'll see in this PR.