blitzServer.at is not a function error when running "blitz generate resource test"

### What is the problem?

I get `blitzServer.at is not a function` error when I try to generate anything (resource, all, queries, etc.) using blitz in a freshly created project.

### Paste all your error logs here:

```
Loaded env from projectDir/.env.local
Loaded env from projectDir/.env
TypeError: blitzServer.at is not a function
at /usr/local/lib/node_modules/blitz/node_modules/@blitzjs/generator/dist/index.cjs:309:75
at Generator.next ()
at fulfilled (/usr/local/lib/node_modules/blitz/node_modules/@blitzjs/generator/dist/index.cjs:273:24)

```

### Paste all relevant code snippets here:

```
blitz generate all test
```

### What are detailed steps to reproduce this?

1. Run `blitz new test`
2. Go to the project directory
3. Run `blitz generate all test`

### Run `blitz -v` and paste the output here:

```
Blitz version: 2.0.0-beta.20 (global)
Blitz version: 2.0.0-beta.20 (local)
Linux 6.0 | linux-x64 | Node: v14.19.3

Package manager: npm

System:
OS: Linux 6.0 Fedora Linux 37 (Workstation Edition)
CPU: (8) x64 Intel(R) Core(TM) i5-8250U CPU @ 1.60GHz
Memory: 3.99 GB / 11.59 GB
Shell: 5.9 - /usr/bin/zsh
Binaries:
Node: 14.19.3 - /usr/bin/node
Yarn: Not Found
npm: 8.19.0 - /usr/local/bin/npm
npmPackages:
@blitzjs/auth: 2.0.0-beta.20 => 2.0.0-beta.20
@blitzjs/next: 2.0.0-beta.20 => 2.0.0-beta.20
@blitzjs/rpc: 2.0.0-beta.20 => 2.0.0-beta.20
@prisma/client: 4.6.0 => 4.6.0
blitz: 2.0.0-beta.20 => 2.0.0-beta.20
next: 12.2.5 => 12.2.5
prisma: 4.6.0 => 4.6.0
react: 18.2.0 => 18.2.0
react-dom: 18.2.0 => 18.2.0
typescript: ^4.8.4 => 4.9.4
```

### Please include below any other applicable logs and screenshots that show your problem:

_No response_