Rinku is the ship between the Vocaloids Hatsune Miku and Kagamine Rin, and it should be canon, here is my opinion on a 10 reason list. A lot of this is either speculation or from Project Diva/Mirai so take all of this with a grain of salt. My sources are mostly personal experience from playing the project diva and project mirai games or just reasoning stuff. 

10. They were released in the same year. ACT1 Kagamine Rin and V2 Hatsune Miku were released the same year. This means they would have(If they were humans) experienced similar life events. 

9. Their voices harmonize nicely with each other. Rin, of course, harmonizes best with Kagamine Len because they were both voiced by Asami Shimoda. However, Rin sounds nice when paired with Miku. Examples include, Seraph on the ring, Poster Girls Prank, Summer Idol, Doki Doki Yuri Gakuen, Doppelganger Identity, etc. 

8. They have a nice color scheme when  paired together. Miku is green and Rin is yellow, so they have a nice analogous color scheme. 

7. Vocaloids have no canon personality, so there is nothing from saying that they aren’t canon. 

6. The opening song for  Project Diva: 2nd is Kocchi Muite Baby by Ryo. There is a line in this song where Miku says guys are stupid. (オトコってバカばっかね)

5. In Project Mirai, Rin and Miku kissed. Not only did they kiss, they kissed in front of a RAINBOW. This was in a song as opposed to an opening or cutscene, so it holds little footing, but they still kissed, in front of a RAINBOW. 

4. In many songs in the PjD series, they have repeated romantic encounters. (Doppelganger, Summer Idol, Colorful Melody, Reverse Rainbow, Promise, Rin-Chan Nau, etc.)

3. In Summer Idol, at the end they decide that they should just be a couple. This was just a one off line, but the song was written by Oster Project, and her opinion holds a bit more footing than others (If you know you know). 

2.  You can purchase stickers from 5 below with an Image of Kagamine Rin with a rainbow behind her. This could be read in an amalgamation of ways, firstly, it’s well known the rainbow represents the LGBTQ+ community. However, it could also allude to the song Promise, or Reverse Rainbow (This is the one where they kiss.) Now, this is all just speculation but the stickers also had references to Sing and Smile by Ren:G and Electric Angel by Giga, so assuming it might be a reference isn’t too far off. 

1. In the Project Diva 2nd Opening, they kissed. Well, they almost kissed. Luka interrupted them. Also, they slept next to each other on the bus. In addition, their names are also under a love umbrella in the classroom, along with a drawing of them on the chalkboard.

All in all this is just my opinion so please don’t attack me ;_; Rinku is at least a possibility in the Project Diva and Project Mirai. Again this is mostly speculation, leave me alone. Also writing my first article of the year on a ship between two robots is … not what I expected but I wanted to so plz leave me alone.