write-nuget-config.sh resolves paths properly (#4193)

# Description of Changes

The script was running `cd` but using the STDB path as passed, so if it
was run from e.g. the root directory, it would generate incorrect paths.

# API and ABI breaking changes

None

# Expected complexity level and risk

1

# Testing

- [x] Running `sdks/csharp/tools~/write-nuget-config.sh .` from the root
directory generates a `NuGet.Config` that uses correct paths

Co-authored-by: Zeke Foppa <bfops@users.noreply.github.com>

Author: bfops

sdks/csharp/tools~/write-nuget-config.sh

@@ -1,6 +1,6 @@
 set -ueo pipefail
 
-SPACETIMEDB_REPO_PATH="$1"
+SPACETIMEDB_REPO_PATH="$(readlink -f "$1")"
 
 cd "$(dirname "$(readlink -f "$0")")"
 cd ..