Dockerfile not found when running `docker build`

### Description of the bug:

I'm having an issue with the `docker build` command. It seems the Dockerfile was not found as indicated by the error 'failed to solve: failed to read dockerfile: open Dockerfile: no such file or directory'. I have tried running the command in the correct directory. Please help.

PS D:\gemin_full> docker build -t gemini-fullstack-langgraph -f Dockerfile .
[+] Building 0.0s (1/1) FINISHED docker:desktop-linux
=> [internal] load build definition from Dockerfile 0.0s
=> => transferring dockerfile: 2B 0.0s
ERROR: failed to solve: failed to read dockerfile: open Dockerfile: no such file or directory

View build details: docker-desktop://dashboard/build/desktop-linux/desktop-linux/p5q5sqhlqcvo5qst6iv47nu4r
PS D:\gemin_full>

### Actual vs expected behavior:

_No response_

### Any other information you'd like to share?

_No response_