Add Pccw parser

[snitass]

This code implements parsers for PCCW (a telecommunications company) circuit maintenance email notifications. It consists of two main classes:

HtmlParserPccw: Parses the HTML content of maintenance emails to extract:

• Provider name (PCCW Global)
• Customer account information
• Maintenance window start and end times

SubjectParserPccw: Parses the email subject line to extract:

• Maintenance ID
• Status (defaults to COMPLETED)
• Summary information

The parsers use regular expressions and string manipulation to extract relevant information from the email content. The datetime values are handled in a specific format ("%d/%m/%Y %H:%M:%S") and converted to timestamps.

[chadell]

In the CI, there is an error due to Python 3.8 support:

    def _extract_maintenance_window(self, soup: ResultSet) -> tuple[datetime, datetime]:
E   TypeError: 'type' object is not subscriptable

-> The syntax tuple[datetime, datetime] is subscriptable typing, which is supported only in Python 3.9+.
Because Python3.8 is EOL, I'm gonna drop support in develop for the next release.
#302

[chadell]

LGTM, many thanks @snitass !