simplify code and update docs (#9)

* rename workspace to working-directory
* update readme
* cache binary in temporary directory
* remove entrypoint.sh
* add cache test
* remove cache

.github/workflows/test.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Run gcov2lcov-action
         uses: ./
         with:
-          workspace: testdata
+          working-directory: testdata
       - name: Diff
         run: diff -y coverage_expected.lcov coverage.lcov
         working-directory: testdata

README.md

@@ -10,11 +10,19 @@ uses [gcov2lcov](https://github.com/jandelgado/gcov2lcov) under the hood.
 
 ### `infile`
 
-**Required** Name of the go coverage file. Default `coverage.out`.
+**Optional** Name of the go coverage file. Default `coverage.out`.
 
 ### `outfile`
 
-**Required** Name of the lcov file to write. Default `coverage.lcov`.
+**Optional** Name of the lcov file to write. Default `coverage.lcov`.
+
+### `version`
+
+**Optional** Name of the specific gcov2lcov program version. Default `latest`.
+
+### `working-directory`
+
+**Optional** Name of the change to specific working-directory.
 
 ## Outputs
 
@@ -23,10 +31,12 @@ No outputs.
 ## Example usage
 
 ```yaml
-uses: jandelgado/gcov2lcov-action@v1.0.4
+uses: jandelgado/gcov2lcov-action@v1.0.5
 with:
-  infile: coverage.out
-  outfile: coverage.lcov
+  infile: coverage.out        # optional, default filename is `coverage.out`
+  outfile: coverage.lcov      # optional, default filename is `coverage.lcov`
+  version: v1.0.4             # optional, use specific `gcov2lcov` release version
+  working-directory: testdata # optional, change working directory
 ```
 
 ### Full example

action.yml

@@ -14,19 +14,20 @@ inputs:
   version:
     description: "gcov2lcov version"
     required: true
-    default: v1.0.4
-  workspace:
-    description: "working directory"
+    default: latest
+  working-directory:
+    description: "change working directory"
     required: false
 
 runs:
   using: composite
   steps:
-    - name: Run gcov2lcov
-      run: ${{ github.action_path }}/entrypoint.sh
-      shell: bash
+    - shell: bash
+      run: 'set -x && curl -sLf "${RELEASE}/${NAME}.tar.gz" | tar zxf - --strip 1'
+      working-directory: /tmp
       env:
-        INFILE: ${{ inputs.infile }}
-        OUTFILE: ${{ inputs.outfile }}
-        VERSION: ${{ inputs.version }}
-        WORKSPACE: ${{ inputs.workspace }}
+        NAME: "gcov2lcov-linux-amd64"
+        RELEASE: "https://github.com/jandelgado/gcov2lcov/releases/${{inputs.version}}/download"
+    - shell: bash
+      run: set -x && /tmp/gcov2lcov-linux-amd64 -infile "${{ inputs.infile }}" -outfile "${{ inputs.outfile }}"
+      working-directory: ${{ inputs.working-directory }}