new inputs activate-environment and working-directory (#381)

venv activation was implicit when python-version was supplied. This now
only happens when activate-environment is true. working-directory
controls where we work and thus also where the .venv will be created

Closes: #351
Closes: #271
Closes: #251
Closes: #211

src/utils/config-file.ts

@@ -0,0 +1,46 @@
+import fs from "node:fs";
+import * as core from "@actions/core";
+import * as toml from "smol-toml";
+
+export function getUvVersionFromConfigFile(
+  filePath: string,
+): string | undefined {
+  core.info(`Trying to find required-version for uv in: ${filePath}`);
+  if (!fs.existsSync(filePath)) {
+    core.info(`Could not find file: ${filePath}`);
+    return undefined;
+  }
+  let requiredVersion: string | undefined;
+  try {
+    requiredVersion = getRequiredVersion(filePath);
+  } catch (err) {
+    const message = (err as Error).message;
+    core.warning(`Error while parsing ${filePath}: ${message}`);
+    return undefined;
+  }
+
+  if (requiredVersion?.startsWith("==")) {
+    requiredVersion = requiredVersion.slice(2);
+  }
+  if (requiredVersion !== undefined) {
+    core.info(
+      `Found required-version for uv in ${filePath}: ${requiredVersion}`,
+    );
+  }
+  return requiredVersion;
+}
+
+function getRequiredVersion(filePath: string): string | undefined {
+  const fileContent = fs.readFileSync(filePath, "utf-8");
+
+  if (filePath.endsWith("pyproject.toml")) {
+    const tomlContent = toml.parse(fileContent) as {
+      tool?: { uv?: { "required-version"?: string } };
+    };
+    return tomlContent?.tool?.uv?.["required-version"];
+  }
+  const tomlContent = toml.parse(fileContent) as {
+    "required-version"?: string;
+  };
+  return tomlContent["required-version"];
+}