chore: stack trace for failed change detection (#1799)

## Why

When SDK changelog generation fails due to a panic, e.g.: a nil pointer
exception, we swallow the stack trace and log an error.

## What changed?

Extended the logged error with stack trace after recovery. This helps us
find the root cause of changelog detection issues.

Author: danielkov

internal/sdkchangelog/sdkChangelog.go

@@ -3,6 +3,7 @@ package sdkchangelog
 import (
 	"context"
 	"fmt"
+	"runtime/debug"
 
 	changes "github.com/speakeasy-api/openapi-generation/v2/pkg/changes"
 	"github.com/speakeasy-api/speakeasy/internal/log"
@@ -21,7 +22,8 @@ type Requirements struct {
 func ComputeAndStoreSDKChangelog(ctx context.Context, changelogRequirements Requirements) (changelogContent string, err error) {
 	defer func() {
 		if r := recover(); r != nil {
-			log.From(ctx).Errorf("Panic recovered in ComputeAndStoreSDKChangelog: %v", r)
+			stackTrace := string(debug.Stack())
+			log.From(ctx).Errorf("Panic recovered in ComputeAndStoreSDKChangelog: %v\nStack trace:\n%s", r, stackTrace)
 			changelogContent = ""
 			err = fmt.Errorf("panic occurred during SDK changelog generation: %v", r)
 		}