Fix STAC `proj:` values and project extension schema for existing items

1. projection extension schema version should be v1.1.0
2. proj:epsg should be type int and proj:shape should be type List[int]

Context

I was debugging an issue on VEDA where epsg was being read as a float and causing some issues.

import pystac
from pystac.extensions.projection import ProjectionExtension

item = pystac.Item.from_file("https://staging-stac.delta-backend.com/collections/nceo_africa_2017/items/AGB_map_2017v0m_COG")
print(ProjectionExtension.has_extension(item))  # False
print(item.properties["proj:epsg"])  # 4326.0

I decided that maybe there was a mismatch between the STAC version and the extension version, so I pulled the file locally (using wget) and changed proj ext schema version from v1.0.0 to v1.1.0

import pystac
from pystac.extensions.projection import ProjectionExtension

item = pystac.Item.from_file("AGB_map_2017v0m_COG")
print(ProjectionExtension.has_extension(item))  # True
print(item.properties["proj:epsg"])  # 4326.0

This time the proj ext is understood, but since "proj:epsg" is stored as a float in the STAC item json it is in the properties dict as a float.

I opened a ticket on pystac to track try to get type coersion based on extension support (https://github.com/stac-utils/pystac/issues/1044) but in this is still something that VEDA should correct in its own STAC.