I could not find an up to date question about how to sync an Office 365 calendar to Google calendar. I do not wan't to use an application designed to use the desktop version of Outlook like OggSync and similar software. I want it to be done only using the web apps without me having to update it every time I make a new calendar event, it should be done automatically.
The solution is to log into Office 365 via https://portal.office.com, click on Calendar and then click on Calendar again under "My app settings". Go to publish calendar and publish the desired calendar. Copy the ICS url created.
Log into Google Calendar and click the arrow on "Other calendars". Click the button "Add by URL" and paste the .ics link from Office 365. Google Calendar is now automatically updated with new events from Office 365 calendar.
The best option I've found is to use Microsoft Flow with the Copy new events in Office 365 to Google Calendar and send a notification template.
Events doesn't show up immediately, but it takes around 5 minutes. Pretty good. It also handles event updates.