fix: configuration file path join on windows

[wengys]

在configuration.ts中，存在一处路径硬拼接问题。可通过以下步骤重现：

于windows平台

1. npm init midway -- --type=web my_midway_app
2. npm run dev
3. 报错了

此提交改为path.join拼接路径

[gitpod-io]

[codecov-io]

Codecov Report

Merging #984 (44e681d) into 2.x (0a2a4e5) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##              2.x     #984   +/-   ##
=======================================
  Coverage   86.42%   86.42%           
=======================================
  Files         203      203           
  Lines        7984     7984           
  Branches     1588     1588           
=======================================
  Hits         6900     6900           
  Misses       1036     1036           
  Partials       48       48           

Impacted Files	Coverage Δ
packages/core/src/context/configuration.ts	97.72% <100.00%> (ø)

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[waitingsong]

join(`${packageBaseDir}`, 'configuration');

可以不需要使用模板字符功能吧

join(packageBaseDir, 'configuration');

[czy88840616]

的确是，不需要模版了

[wengys]

确实是，昨晚改的不细致