ROADMAP.md: Re-arrangements around the parsing aspect

This is mainly motivated to decouple earlier from lxml, so that it
isn't a burden when refactoring to the native implementation and to
be more confident that the result will have a stable API.

ROADMAP.md

@@ -2,20 +2,43 @@
 
 ## 0.6
 
+- move `_delb.parser.ParserOptions` to the `delb.parser` package
+- remove `_delb.TagNode.parse`
+- provide a `delb.parser.parse` function as replacement, re-expose it in the `delb`
+  module
+- how should the otherwise equivalent function to parse a node sequence be called?
+    - or explicity `parse_one_node` and `parse_multiple_nodes`?
+- the tree building will be based on (SaX-like) event parsers for which a common
+  abstract interface needs to be defined, considering concrete implementations of
+  adapers for:
+    - `lxml.etree.XMLPullParser`
+    - `xml.sax`
+    - possibly a Python wrapper for `quick-xml` in a separate package
+    - maybe even a `re` based one for platforms where none of the above is available
+- what should be defined as common behaviour configuration options?
+    - except `resolve_entities` the current ones of `ParserOptions` are fine as such imo
+    - possible extension: an option that forces coercions from CDATA to text nodes
+- move parsing from loaders to the `Document` class, thus breaking their interface
+    - they're then supposed to return a file-like object
+- remove `_delb.plugins.core_loaders.etree_loader`
+    - if lxml objects as input is a future use-case, a conversion should be maintained
+      in a separate package
+
+## 0.7
+
+- drop support for Python 3.7 & 3.8
 - a native implementation of the data model
 - add a node type for CDATA
-- move parsing to a separate module with a dummy parser that still uses lxml as backend
 - provide means to build a wheel with *mypyc*
-  - but don't publish a mypycified wheel yet
+    - but don't publish a mypycified wheel yet
+- declare the API as mostly stable
 
-## 0.7
+## 0.8
 
-- a native XML parser
-- re-add the argument `parser` for `delb.Document`
-- deprecate `parser_options` of `delb.Document`
-- make `_delb.plugins.core_loaders.etree_loader` an extra option
+- declare the API as stable, from now on new features should be released under
+  a "preview" notion
 
-## 0.8
+## 0.9
 
 - drop any remaining checks against lxml equivalents
 - remove all remaining deprecated features