Use "go get" or "go install" selectively

Go 1.18 dropped support for installing binaries via "go get", Go <= 1.16
does not support it. So we need to use the right verb depending on the
Go version.

.github/workflows/tests.yml

@@ -17,11 +17,13 @@ jobs:
           - job_name: Windows
             go: 1.18.x
             os: windows-latest
+            install_verb: install
 
           - job_name: macOS
             go: 1.18.x
             os: macOS-latest
             test_fuse: false
+            install_verb: install
 
           - job_name: Linux
             go: 1.18.x
@@ -29,26 +31,31 @@ jobs:
             test_cloud_backends: true
             test_fuse: true
             check_changelog: true
+            install_verb: install
 
           - job_name: Linux
             go: 1.17.x
             os: ubuntu-latest
             test_fuse: true
+            install_verb: install
 
           - job_name: Linux
             go: 1.16.x
             os: ubuntu-latest
             test_fuse: true
+            install_verb: get
 
           - job_name: Linux
             go: 1.15.x
             os: ubuntu-latest
             test_fuse: true
+            install_verb: get
 
           - job_name: Linux
             go: 1.14.x
             os: ubuntu-latest
             test_fuse: true
+            install_verb: get
 
     name: ${{ matrix.job_name }} Go ${{ matrix.go }}
     runs-on: ${{ matrix.os }}
@@ -65,7 +72,7 @@ jobs:
       - name: Get programs (Linux/macOS)
         run: |
           echo "build Go tools"
-          go get github.com/restic/rest-server/...
+          go ${{ matrix.install_verb }} github.com/restic/rest-server/cmd/rest-server@latest
 
           echo "install minio server"
           mkdir $HOME/bin
@@ -97,7 +104,7 @@ jobs:
           $ProgressPreference = 'SilentlyContinue'
 
           echo "build Go tools"
-          go get github.com/restic/rest-server/...
+          go ${{ matrix.install_verb }} github.com/restic/rest-server/...
 
           echo "install minio server"
           mkdir $Env:USERPROFILE/bin
@@ -187,7 +194,7 @@ jobs:
       - name: Check changelog files with calens
         run: |
           echo "install calens"
-          go get github.com/restic/calens
+          go ${{ matrix.install_verb }} github.com/restic/calens
 
           echo "check changelog files"
           calens
@@ -229,7 +236,7 @@ jobs:
 
       - name: Install gox
         run: |
-          go get github.com/mitchellh/gox
+          go install github.com/mitchellh/gox
 
       - name: Cross-compile with gox for ${{ matrix.targets }}
         env: